Help navigating car/train transportation London/Bath/Edinburgh

They may exist but am unaware of any car rental drop that will shuttle to a train station. Personally I would drop the car and call a taxi. The car rental drop will call a cab for you. It is easy via train or bus to get between London and Bath. You really do not need a car unless you have a specific reason.

If you're committed to taking the train to Edinburgh, why are you mentioning airports ("I've read to pick up train outside London so have been looking at Heathrow or Gatwick since our 1st stop is Box Hill.") ?

You could drop off your car in Bath, then take the train from Bath to London to connect to the train to Edinburgh, couldn't you? That way you could enjoy your stay in Bath without the hassle of parking etc. I Googled "car hire Bath UK" and I see several choices, including Enterprise, Europcar, Hertz and Indigo.

Frank, yes, we are visiting several places on the way to Bath over a few days so we do need a car. Yes, a taxi could work although I am trying to minimize costs if possible so a possible 30 minute taxi ride sounds expensive.
Epltd, the only reason I am mentioning airports is that car rental places tend to be located there. So far the car rental places that I have checked when you put in Bath as a drop off, expect you to drop off in Bristol. And taking the train to Edinburgh from Bath costs a lot more than from Bristol. I'd be happy not to go to an airport at all!

I'm still not clear on what you're trying to do. Your original post probably needs editing. It sounds like you don't plan to sleep in Bath but are just trying to find a convenient mid-point. Is that right?

In Bath, per the summary in Rick's guidebook: Enterprise and Thifty both can provide a local transfer to your hotel or train station; National/Europcar (which I used) is about 7 pounds by taxi to/from the train station, and Hertz slightly closer.

Beware of limited hours car rental on weekends.

If you're booking train tickets well ahead, then cost differences shouldn't be such a big deal.

Bath has a number of national car hire company offices. Hertz is nearest the railway although Alamo and Enterprise aren't far away either.

Bath cannot cost a tremendous amount more than Bristol on the train, although traveling from Bath would need a change in Bristol

okgals, just to understand, you are planning to drive from London to Bath, then take a train to Edinburgh? Do you need to drive back to London for any other reason than to return the car? Do you have to drive to Bath, or can you take the train from London to Bath?

If you absolutely need the car in Bath, perhaps you could drop the car in Bristol and take the train to Edinburgh from there without going back to London.

I've read to pick up train outside London

I don't understand that. Can you please say what you have been told? By somebody who actually has used trains here?

The great thing about trains is that they go everywhere from everywhere, and you use the station near you and make changes to get to your destination.

What advantage have you been told you will get by going to a remote station?

To get to Box Hill take the train from Victoria. 55 minutes to Boxhill & Westhumble.

Ok I think I get where you're coming from. You're looking at airports because your journey starts in central London but you don't want to be driving in the middle of the city - that's understandable. You mention Bristol because it has an airport, not that you want to go there. So my advice is forget the airports and as Nigel said take the train to Box Hill and Westhumble (it's a delightful little place). Not sure where you are staying but maybe it's walkable or otherwise phone for a Dorking based taxi. I would then recommend hiring a car from Enterprise in Dorking. They will deliver the car to your door, albeit if you want it on a weekend they will tend to deliver it on a Friday. There will be a £40 excess to drop off in Bath but this is probably cheaper and less stressful than back tracking and getting trains over to Bath. Again with the return they May pick it up from where you are staying but with timings being uncertain you might need to go to their depot which is 2.5 miles from the station so a bus or taxi ride should be factored in.

Enterprise will also take you to a local destination once you've dropped the car off.

Everyone, I'm sorry if my questions were not clear. I'll try again:

In London for a week, then plan is to rent car to visit Jane Austen sites, starting with Box Hill. Staying overnight in Chawton, Portsmouth and Lyme 1 night each and then driving to Bath, where we will be staying 3 nights. After that we plan on taking a train to Edinburgh.

So I'm trying to figure out the best place to pick up and drop the rental car, taking cost, time and ease of travel logistics (getting to rental agency from London and to train to go to Edinburgh) into consideration. I've been told/read to not pick up a car in London dt congestion and that charge one incurs driving there.

You all have given me some good ideas to explore.

I recommend that you also consider visiting Winchester Cathedral (where Jane Austen is buried). The house in which she died is nearby.

From Bath, you will be taking a train to Edinburgh. You will start off with a short hop to Bristol (Temple Meads) = the downtown station. Then train north. Some trains go direct to Edinburgh but take a longer route via York. All well and good if you would like to break the journey and stay a night or 2 in York - although it would be better to do this if returning south to London from Edinburgh.

A Bristol to Edinburgh journey can be around 1 hour less by changing from Cross Country Trains to Virgin Trains at Birmingham (New Street). If you pre-purchase separate tickets for the 2 legs, it can work out cheaper than buying 1 through ticket from Bath to Edinburgh. See www.nationalrail.co.uk and check prices for your date. (Another split in the ticket at Cheltenham Spa can also sometimes reduce the prices - even though you stay sitting on the same train).