Is this after your London stay, discussed in another thread? I saw that Hampton Court is on your list of places to visit in the London thread. You don’t need a car to get from London to Hampton Court. It’s a day trip on a commuter train. It’s really a one day outing.

Or, is this the start of a longer road trip? If yes, then you should also be considering where you want to end the trip and drop off the car. Check on any one-way drop off charges.

Hammersmith is west of the center, but, I haven’t rented from anywhere but Heathrow, so cannot advise you. A Heathrow rental is not suitable, as it’s further away from the city than Hampton Ct.

'I want to pick up a car outside the busy metro area.' Hammersmith doesn't fit the remit, as it's part of a large busy metro area.

If you don't want to take the 111 bus then the Underground to Earl's Court is an easy trip from Heathrow. There is a lift from the Piccadilly line to a walkway around the perimeter of Earl's Court station to the useful mid platform lifts for District line trains to Wimbledon (also step free) for a train to Hampton Court.

Yes, sorry--this is the start of a road trip, after 5 days in London. I want to spend the night near HC, attend a tour of West Horsley Place in the morning (I'm a huge "Ghosts" fan LOL), visit HC in the afternoon,and spend a second night in the HC-area hotel. I'll then head up to the Cotswolds for a few days.

I think flying back out of LHR will be my best bet, so I can drop off the car at the same location if need be. If it doesn't cost much more, I'll just drop it near LHR and grab an airport hotel for the night before flying out.

I clearly have no understanding of what the UK looks like outside of London--I assumed Hammersmith must be a small town in the countryside! Reading Charles Dickens has clearly not prepared me for this trip... ;-P

Hampton Court and surrounding area is commuter land - you will have limited choice for hotel options there. The trains from central London are frequent.

If you intend to return the car to Heathrow, then it makes sense to hire from there. In the US you expect airport rentals to cost more than city centre pickup - the reverse is true in the UK

Also, if it matters, it looks like I'll be staying near Trafalgar Square. Shockingly, Z Hotels just emailed me to say they'll credit me for the non-refundable rooms I paid for just before Covid hit. :-)

Just put Hammersmith in a Google map, it’s only 2 miles west of the Natural History Museum in South Kensington. It’s just a neighborhood of West London, now.

Reading Jane Austen doesn’t help with knowledge of modern London, either. Richmond was deemed as so much closer than London to whatever village Emma lived in. It’s 11 miles from St. Paul’s. Hampton Court Palace is less than 16 miles from St. Paul’s. Distance mattered when it was done in a carriage or on horseback, or on a boat on the Thames. I live in a NYC suburb, commuted 27 miles each way to work every day. London has similar commuters.

If you're staying near Trafalgar Square then take the train from Waterloo station to Hampton Court.

'I assumed Hammersmith must be a small town in the countryside!' Hammersmith is in zone 2: https://content.tfl.gov.uk/standard-tube-map.pdf West Horsley Place is near Guildford, also in the commuter belt. If you must visit the Cotswolds then hire a car at Heathrow or in Oxford - with the latter you can travel from and to Heathrow by coach.