UK - how to tour it?

It also means being out for a week and need to pack for that and fly with a checked bag which will up the price, even for a smaller craft maybe operated by Eastern Airways getting out of Cardiff, and I figure I can do my laundry in Wales since they'd need attention from Scotland and I guess why not find a laundrette in Cardiff, and then go off on the Belfast leg and return home and do my laundry again in London when I'm home and I've toured the UK.
This also means I can pack stuff and fly to Belfast with gifts and post it home?
But what about Brexit? and NI and our internal customs union...
Should I just post mementos and souvenirs and stuff back to myself from Cardiff and maybe return home to find a bunch of notes telling me to pick up undelivered stuff from the depot in Croydon (not even in my own neighbourhood) or better yet... Could I send something addressed to me but not to my house, to my local Post Office on my own High Street/within my Neighbourhood.
Would I have to get a PO Box?

I like to shop, I like to travel light, so maybe I could send stuff home?

 

So, Scotland, Wales, fine with my part of England.
Northern Ireland however, Belfast, the only leg I've paid for, are all like;

https://www.nidirect.gov.uk/articles/coronavirus-covid-19-travelling-within-common-travel-area

and of course they're like £70.00 because they're £7.00 each and only come in packs of 10.


Here's where I get to submit the results.
https://www.gov.uk/report-covid19-result

 

May as well milk my 10 pack of tests and go for Dublin and Amsterdam, go to Amsterdam, get stoned, go to Dublin for St. Patrick's Day and get and drunk and do my locator form and have 2 nights a piece.
My stoned and drunk tour. £70.00 10 pack test my foot.
So...

Arrive on the Ides of March, 15th/16th Cheech and Chong it, 17th fly off to Dublin, St. Patrick's Day, 18th, hangover, 19th fly home to London.

Would I have to self isolate anywhere for a plan like that armed with 8 Covid Test Kits and needing 5 nights in 2 countries (3 if you count my own).

I wonder if I'd have to self isolate if I flew in from London in Amsterdam or in Dublin if I flew in from Amsterdam?

 

So I just worked out the trains in Cardiff/Wales and Bridgend.
... It's £5.00 to get from the hotel to the airport by train and the flight to Belfast takes off @ 10:45 and arrives in Belfast @ 12:10 and there's 1 train to Cardiff Airport that takes half-hour at 07:40 and 1 train change at Bridgend that takes an hour if I miss that 07:40 train at 8:00... But Cardiff Airport's telling me it wants me at the airport 2 hours but if I arrive at 9:00 having missed that 07:40 train, the airline is telling me check-in closes 30 minutes before so 10:15, I'd still have an hour.
the 08:40 train gets to the airport 5 minutes after the Bridgend train anyway, so if I miss the 07:40 train, could just wait an hour for the next one and arrive 9:10 at the latest for a 10:45 flight to make check-in for 10:15, which sounds more fun than Edinburgh's get out early to catch my flight back to London so I can be on the coach to Cardiff in the morning, but I could sleep on the bus if I'm tired.
I think Edinburgh sees me checking out at 03:45 and walking to a bus stop at 4:00 to make a 06:00 flight, giving myself 1 hour and a half at the airport (half-hour more than the airline advised me for that domestic flight).

I'm sort of sure I can walk to the Cardiff hotel from the bus station and the bus will take me to Cardiff from the terminal at the airport in London and arrive around check-in in the early afternoon; if I check-out of Edinburgh in the middle of the night and get the plane to my bus at back in London, but not in London that it'll be so close to my house, but in London on the edge out by the airport so I won't feel the need to want to go home and just check up on anything or put my bags down or nothing, just remove the temptation by taking a bus directly from the airport rather than London's bus station where I would feel the urge to just pop in, feed a cat and sit down and even waste a day.

 

Okay, I've worked out a couple of things.

...

Here goes;
I want 1 day in Edinburgh doing a city tour/hop on/hop off bus.
I want a buy a Scottish flag and things, this will be a Sunday and I'd arrive in the afternoon because check in is at 3 pm and I can land, check in, and still go shopping and see the city.
I also want to take a tour of Loch Ness and the Highlands, and that's 12 hours and will eat up my Day 2 from 7 am to 8 pm, where I'd want to wind down at a bar somewhere and do a night crawl then have an early night to check out on my night 2 rather early at like 3:40am for an early flight back to London where I want to get a bus to Cardiff from the airport, so, rtn ticket from London, but instead of going home when I land back in London, get on the first bus, and the first flight lands with an hour to spare for this first bus to Cardiff, arrive in Cardiff 13:30 and check in time.

Sleep, do laundry so, find a laundrette and buy a Welsh flag and things and find a post office to post my Wales and Scotland things home so I don't have to worry about Brexit and Northern Ireland.
What I want in Cardiff will be open on Wednesday which will be my Day 2 in Cardiff.
It's this Flea Market, turns out there's not a lot of stuff I want to do in Cardiff, so, eat local stuff (Welsh Cakes for sure) and try and find something cool and unique to post home from the flea market maybe.
I don't mind not doing touristy stuff in Cardiff, I like relaxing and just exploring and doing my chores like washing and stuff, and my clothes I wore in Scotland should be clean and dry ready for Belfast if I do my laundry in Cardiff, got nothing better to do except shop and eat there, so, may as well do my laundry too in Cardiff.

Belfast, I want to do a lot in Belfast, on Day 1, which means; shopping for Northern Irish flag and things, guitar shop, maybe a taxi tour of the troubles, maybe Titanic experience...
Day 2 in Belfast will be Giant's Causeway and scary looking Rope Bridge I've never heard of looks pretty, might or might not be eating up my day from 08:45 am it leaves and its 9 hours long.
6 pm back in Belfast, IDK, enjoy the evening, wind down, IDK.

I like the idea of; only having 2 nights in each city, and using my 1st day to see the city, and the 2nd day to see something I've always wanted to see in that country; and I like that I want to do much in so little time, that I'm going to be sight seeing and transit for a week with only my evenings and days and Cardiff to myself.

 

At the end of it all, I can see myself looking for an England flag on Oxford Street to complete my collection lol.
In fact, it's no accident I'm landing back in London on a Saturday, I could enjoy London after a week of going to all these places and doing these things in the UK, just shopping on Oxford Street or even going out Saturday Night in London, whatever, I could enjoy that after that week and wrap it up that way, IDK, I do plan to enjoy London, maybe, that day.
Land Saturday morning, go home, head off to London see if I could find some flags like the England flag and a Union Jack maybe to complete my collection, IDK, and shop in London and go home and head back out and enjoy London at night, then come home, put my head down and I'd have seen the UK and had a homecoming for it too enjoying London, IDK, just random thoughts and reasons on why I like coming home on Saturdays a lot, to get a good home coming from London and to get my head used to home again; I'm not sure if I'd need to readjust to London since I'm not leaving UK, but I've done that for the US and Amsterdam, either way, I can see myself on Oxford Street that day looking for an England flag to match, and since I just saw the UK in that week of sight seeing and transit tour where I doubt I'd get to plant roots, just experience and go, after that week of touring the UK.

It's a mad schedule I guess for doing so much, but rather than add days, I want to instead just always be thinking of getting to where I've got to be all week and seeing stuff and buying stuff along the way.

That's all I'm going to be doing really.

Like I gotta be at this place at this time to catch the bus that leaves here at this time or I've got to be on the way to this airport at this time for a flight that takes off at this time, and from that, working out what, if any, to do with my own time in that and being in a new city as I'm trying to figure that out - like in Edinburgh, I've got 2 hours in the evening on day 2 to kill after I've done everything I could think of, and so could Edinburgh from 20:00 to 21:30, just, I'm thinking, bar, whiskey, night walk.
Cardiff I've got pretty much 2 days not to care there, so...
Laundry, chores, flea market appeals to me there, welcome to Croydon Cardiff - although I could buy a bunch of touristy Welsh stuff there and eat Welsh Cakes, and plan to.
Then Northern Ireland I should be ready for from taking it easy in Cardiff where I'd be doing everything I want to do in Northern Ireland for 2 days with Belfast at my feet.