San Francisco to London then Paris and back... need help with planning

Two exciting destinations! I will try to help a bit...

First, 8 nights is 7 full days for your trip. Arrival day is pretty well lost as you will all be groggy and departure day is a loss completely unless you leave in the evening from Paris (unlikely). LMK if I am wrong.

So two nights London is really one full day and part of arrival day (groggy!) for that great city and all its charm and Harry Potter sites. Can you possibly spend at least 3 nights there, even at an increased cost for the Eurostar on Friday? Premier Inns are clean and safe if not terribly charming, but can be a real,budget saver that would allow you to stay one more night.

On the day you go to Paris, go early so as to not waste any time. You can easily be in Paris by noon so you have that half day to do something. Then you have 4 full days to enjoy Paris. I do not have a hotel recommendation and your budget is light for three people there, IMO, but others may have ideas. Would you accept a B&B in Paris? No concierge but perhaps a helpful host/owner. If so, check out Alcove & Agapes. We had a wonderful experience with them.

If you're considering the Ritz for tea, you might want to consider Fortnum and Mason-it's less expensive than the Ritz but still feels really upscale(the queen shops at this store)and you don't have to dress up-business casual is fine. If you have this late enough in the afternoon, it can be your dinner.

I responded on your France forum question, but it is a London Hotel I sugggested so I will re-post here. ThenDarlington Hyde Park has triple rooms within your budget.

https://www.darlingtonhotel.com/accommodation/

Read my other response for the rest, especially Harry Potter. Book the studio tour now!

Unfortunately, with your time constraints, you won't have time to do much in London. The Harry Potter tour at the Warner Bros studio is pretty much an all day thing, and requires booking months in advance; in fact most of June is already sold out. However you can google HP walking tours to find something that might appeal to your child. At the worst, you can check out the luggage cart in the wall at Kings Cross station on your way to St Pancras to catch he Eurostar.

You will want to pre-purchase those Eiffel Tower tickets ASAP. You might also want to pre-purchase any high demand tickets for London as well.

Great suggestions--thank you all, sounds like the HP excursion won't work, but I like the station idea--- what do you suggest otherwise for the short visit in London?

www.walks.com for the Harry Potter Walks.

You could also visit LeadenHall Market and look for the entrance to Leaky Cauldron. Your child should recognize the market as Diagon Alley.

See Tower Bridge. Might even consider the Tower Bridge Experience if no one suffers from acrophobia.

You can walk in Kensington Gardens by the Palace
( where Prince William and Duchess Kate Live) the nearby Round Pound has water fowl ( kids always like ducks and geese) and on some days people are there with small toy yachts. There are also green parrots loose in the nearby trees.

For your proper tea look at the Wolsley.

In London, a lot depends on your interests, but many sites are free - like the British Museum (for the Elgin Marbles, Rosetta Stone, etc.) or, for paintings, the National Gallery (not too far to walk to Fortnum & Mason for tea afterward). You have such limited time!! Also, consider any of the London Walks that catch your fancy. Have you considered catching some theater in the evening? London is a fabulous city with so much to do!

Having just spent nearly a month in France this past fall and a week of that in Paris, here are some thoughts (others will probably give you similar tips on the France forum):
1) The lines for the Eiffel Tower will eat a lot of time. Consider just looking at it (at night from the Seine when they put on the light show and maybe the view from atop the Arc de Triomphe and/or from the Trocadero).
2) Some galleries at the Louvre are not always open - closed on certain days of the week. Be sure what you want to see is available on the day(s) you go. Speaking of the Louvre, you may want to consider the Paris Museum Pass, especially if you plan a day trip to Versailles (see below) and want to see the Musee d'Orsay (impressionists, etc.) and/or the Rodin Museum, it may be worth your while and save you some time.
3) Even on an overcast day, Versailles is fabulous, but in June will probably be insanely crowded. If possible, book the "King's Apartment tour" and start out there. Versailles can easily fill a day (your daughter will probably be delighted by the story book qualities of the Queen's Hamlet).
Like London, there is much to do and you will have only so much time, so planning is essential.

Have fun!

Buy your Eurostar tickets as soon as possible. Prices will escalate steeply as the travel day nears.

Premier Inns is a U.K. chain with basic (but comfortable) rooms in good locations and more value prices. I’ve been staying at Premier Inn Waterloo and have been quite pleased.

They have a type of room with a double and a day bed

Many museums in London and Paris are open late on Friday nights. We went to the Louvre on a June Friday night and walked right in! :)

Thank you all for your input!!

The Ritz is ritzy and has a pretty strict dress code. Friends wanted to take us there for our anniversary a few years ago, but my husband would have needed a sport coat, nice shoes, etc. It's a bit easier for women to deal with dress codes. They ended up taking us to another nice place that we didn't have to pack different clothes for.

Skip the Ritz and Harrods for tea...instead go next door to The Ritz to The Wolseley. Incredibly reasonable price and a beautiful place for tea that doesn't gouge you. Cream tea or proper afternoon tea (lots of other things too) both on silver service!