We have 11 hours at Heathrow Airport in November, starting at 11:35 am and ending at 10:30 pm. We have been to London before for 3 days, but there were tons of things we missed (obviously). The two that seem like the best options (out of the things we missed) are Windsor Castle and the British Museum. Windsor Castle closes at 4:15, and we'd have to take a cab or rent a car. (There is a bus available, but it seems like a time waste in this case.) I suspect that by the time we got through the border & into a car it would be 12:30 or so. Assuming we don't get lost, we could maybe be to Windsor by 1, giving us 3 hours to see the castle. The remainder of the time would be spent in Windsor. Of lesser importance, the cab or car rental would be rather pricey. Alternatively, we could take the tube to the Museum. The tube ride would be around an hour, but I suspect that we could be on the tube more quickly than we could be in a rental car. So, perhaps we could be to the museum by 1:30. The Museum closes at 5:30 and is free. We could spend any remaining time soaking in London for a couple hours or at the Tate Modern, which is open late on this particular evening (Saturday). Any thoughts? Obviously, the quality of what we see is important, but also which plan do you think would be less stressful? We will, afterall, be coming off an 8 hour flight from Chicago with a 5 hour flight to Tel Aviv still awaiting us.
No need to rent a car or use a cab to get to Windsor. You can use what the British call a 'hire car' or a 'pre-booked car service'. It's liek a cab- but must be arranged ahead of time, and is MUCH cheaper. The journey to Windsor takes about 15 min. If you do a search on the London or Windsor forums on TripAdvisor you'll see lots of info about this- even some recommended companies. LauraRW (stands for Laura of Royal Windsor!!!) posts alot and her recommendations are what I'd go with. I LOVE Windsor castle and the town! Great for a wander (stroll down the Long Walk, or about town or over to Eaton), and excellent for shopping of all kinds. Several good pubs and restaurants. If immigration checks go speedily, and your luggage is checked through, you should be able to have the car service pick you up arond 12:30-12:45 and be there by 1:00ish. 3 hours is plenty for the castle, then walk around the town and have an early supper. Head back around 7:00.
Luggage will be checked through.
Don't forget that even if your luggage is checked through you will still need to clear security so will need to be back at Heathrow with plenty of time to spare. Windsor is always worth a visit - a walk through the grounds, the state rooms, and St. George's Chapel. Lots of interesting shops to look at and places for lunch and/or dinner. Eton and its college is just a short walk away - Eton College Chapel was built around the same time as St. Georges and is well worth a look if it is open. Also, bear in mind that in November in gets dark earlier - probably around 4.30 or so. The BM strikes me as being a great place to spend a November day - especially if the weather is wet. There are food outlets in the museum (I like the ones in the Great Court because it is such an amazing space) or you can find lots of pubs around. However, if "we" includes kids you may not be able to use them unless there is a dining room separate from the bar. I think it might be a bit of a stretch to make the Tate Modern and get back to the airport. London has some great restaurants - why not find one that suits your tastes and have a relaxing meal after all that airline food!
If it were me, and given it is November, I'd probably choose the British Musuem. The tube route is direct from Heathrow to Holborn, so to me that just seems like the easier trip. Do check though to make sure there are no engineering works planned for that weekend. When you are done with the museum, you could decide what to do next ... stop in a pub or cafe for a meal or a coffee, go for a walk, or do something else. I'd plan to get back on the tube between 6:30 and 7, so you won't have tons of time.
I think we might just play the weather. If it looks like a OK day (for England in November), we'll go to Windsor Castle via Windsor Cabs. If not, the museum. Not that we have that settled, it's on to planning two weeks in Israel and deciding if it's worth the hassle to cross the border to see Petra. But that's a topic for another forum.
Re Windsor. parking is difficult, they have a few parking lots but they always seem full. So chose Hire Car or taxi dirrect from heathrow to Windsor. train will work, but will take longer