Hey y'all, I was wondering if anyone had any advice/warnings/comments/thoughts/etc. about an anniversary trip (10 years!) my partner and I are planning for late May. For context, I have been to the UK before a few years back but my partner has not. Also, I'm American and I've never driven anywhere but the US. This is the rough and very basic itinerary:

Day 0: Edinburgh

• Land in Edinburgh
• Check in to hotel
• Wander around the city

Day 1: Edinburgh

• Rent car
• Drive to St. Andrews
• Drive around in the Scottish Highlands

Day 2: Edinburgh > Redmire

• Drive south to a bed and breakfast in Redmire
• Check out the English countryside

Day 3: Redmire > Manchester

• Drive to Manchester
• Turn in car
• Check in to hotel

Day 4: Manchester > Bath

• Take a train to Bath
• Wander around Bath
• Stay at bed and breakfast

Day 5: Bath > London

• Take train to London
• Check in to hotel
• Do touristy things
• Eat a lot of food

Day 6: London

• Anniversary dinner

Day 7: London

• Wander around
• Eat a lot of food

Day 8: London

• Depart from Heathrow

I fully intend to add plan out the details and activities as we get closer, though I would be grateful for any recommendations for things to do or places to see. It's my partner's real first time out of the country and given it's an anniversary trip I wanted it to be mostly relaxed.

The first half or so of the trip is predicated on me, an American who drives on the right, driving good distances in the UK. I've plenty of experience doing long distance driving in the US, it's mostly the driving on the opposite side that concerns me. Is this recommended? Would it be better to just use rideshares or transit in the cities and take trains over the longer stretches between instead of a mini-roadtrip? Thanks y'all!

EDIT:
Thank you everyone for your thoughtful responses! I will try to get to as many as I can as soon as I can!

I am taking a trip soon to London and will possibly be adding a couple days in Paris. It's been a hot minute (few years) since visiting the UK and would like to solicit some timely advice and tips. One thing that comes to mind: How important is it to carry cash? Would I need to pay London and Paris street vendors or any shops with cash or will a card with no exchange fees suffice? While we will of course be visiting some tourist attractions like museums, most of our time will be taken up with book stores, record shops, food and coffee shops.

My wife and I (from the U.S.) are going on vacation and as part of a larger itinerary have scheduled a week in Northern Ireland, based in Belfast. We'll spend the first couple of days decompressing and exploring the city, but besides that I'm wondering what would be worth doing there during that time. I've been focusing on the other parts of our itinerary and have only very limited knowledge of that area and its attractions. We plan on renting a car for a day or two to get out of the city but otherwise will be relying on public transit. Thanks in advance for any recommendations or advice!

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Having never moved further than like an hour away from where I grew up, I'd love to hear about experiences, tips, things to keep in mind when moving to a totally new place. Anything centred on London/the UK is of course very welcome, but I'm also really into hearing from people more generally :)