Best place to park off M3 to catch train into London?

[Winterstormsu]

Can anyone help advise easiest place if driving from SW along A303-M3 to edge M25 to then park for 48hrs to catch train into London? Taking my teen DDs to catch a show & have a night away and at the moment the cost of train is ridiculous (even with railcards) so now looking at whether to drive to edge M25 and then train into London?

Maybe Sunbury? The station is very close to the M3. The station has a car park - not sure of the details, such as advance booking etc but I think it is open 24 hours.

Thanks loads of ideas I’ll check them out to find best combination so we can have a good trip.

Thanks for lots of ideas Farnborough is looking like a good option £5 24hr parking & £15 return on train after 12noon. So if train prices don’t come down in price think we’ll do that option. I’ve looked at coach but one of DDs more likely to get travel sick so would prefer train options. Bonkers though that we make the train prices so crazy that driving is a cheaper option when I’d really rather use the train the whole way! My eldest has a 16-25 railcard and couldn’t use it for college as not allowed before 10am the other does have a 16-17 card and we did have a 2 together at one point I think.

Wanted to add, if you’re considering parking closer in like Richmond, think about whether your car will be subject to ULEZ charges (ie older petrol / diesel cars, larger engine sizes - it’s all online).

Farnborough sounds like a great option