Thanks for the clarification. Claudia from LA may chip in - she really enjoyed her stay in Holborn and knows of a couple of excellent things to do around there. I may be able to find her trip report.
Many tourist attractions don't open until the week of Easter except they are open for half term before that. There just isn't the trade for them and they don't have the staff before that time so they don't open. However all other necessities for life such as shops, hotels, etc., that people need are open year round.
in your situation I would suggest getting your car at Heathrow. Very easy to get to by underground or Elizabeth line from London. Holborn is a great area in general, I think that being based with your daughter there should work out well.
Holborn Underground is on the Central and Piccadilly Lines. To get to Heathrow you can either take the Piccadilly for about an hour and it goes all terminals from whence you can easily get to the car hire by shuttle. It would be the cheapest. You can go one stop on the Central Line to Tottenham Court Road and change there for the Elizabeth Line which will take you straight into the airport as well. Faster but more expensive.
From Heathrow the drive towards the Cotswolds and Stow on the Wold is very simple.
Simply out of the airport onto the M4 motorway to the M25 clockwise to the M40 and follow the M40 to Oxford changing there onto The A44 which will take you very close to Stow on the Wold. If the M25 is plugged up stay on the M4 until you get to junction 8/9 and onto the A404(M) marked for High Wycombe. The A404 is part motorway and then becomes dual carriageway "A" road, an easy shortcut to the M40. At the end in High Wycombe bear left onto the M40 as before.
The reason I don't recommend Oxford to collect a rental car at this time Is that there is huge construction around the railway bridge and around the station on the Botley Road which means that the road is blocked and you cannot get from the Oxford city side towards the Cotswolds side of the Botley Road. When you get your car at Oxford you have to go all the way on a long detour which involves heading into Oxford which is very unfriendly towards cars. And then back out again. I simply don't recommend it although it used to be my first choice to suggest. If Marco from Oxford sees this perhaps he has an update.
note - our Consumer Reports like organisation here, called Which?, has recently said that Enterprise is the most expensive car hire in the country . I have previously had good experiences with them but recently had a less than positive interaction with them near my house here in the countryside of Northamptonshire, north of London.
