The Four Seasons has a stay 2 nights/get 1 free offer for suites and a stay 3 nights/get 1 free offer for some rooms and suites. The offer is good until 8/31 - but availability is limited. You can play around with the website and see what availability you come up with. Note that some of the non-suite rooms are quite large. But - with 4 people - you'll probably want at least 1 1/2 baths (executive suite level or higher). Your cheapest rate for the cheapest room (and I think you'd need 2) would be a little under 39,000 yen a night with the "get one free" offer.
The Four Seasons is a very low hotel (I think rooms are on the 3rd through 6th floors of a large office building). So evacuating wouldn't be as much of a problem if the elevators weren't working as it might be in a taller building. Also - the hotel is very small and has a lot of staff that might be able to help you out in a pinch.
If you book through a Four Seasons Preferred Partner agent - you will get at least 2 adult breakfasts included (don't know what the story is with children - but - if you book 2 rooms - you will certainly get 4 breakfasts) - and a room upgrade if available.
You will have to contact the hotel directly to make arrangements (note that I don't know whether there are handicap accessible suites as opposed to rooms):
Families can be accommodated in suites and, in some cases, through connecting standard rooms – we recommend contacting the Hotel to make the best arrangements. Rooms and floors for non-smokers are available on request. Please contact the Hotel directly to make arrangements for wheelchair-accessible rooms.
FWIW - I was surprised to find out the FSM was voted the #1 family-friendly hotel in Tokyo on Tripadvisor (
http://marunouchi.enewsletters.fours...-for-families/) - so I think it's definitely worth a look.
About the only downside of the hotel IMO is it doesn't have a pool. I don't know if that is important to you.
I also don't know what you want to see in Tokyo. So I can't comment on transportation to/from the hotel. I can say that the area around the hotel is reasonably flat - and that it's pretty close to Ginza and the Imperial Palace and subway stations (and next door to Tokyo Station). I think an area like Ginza will be useful in the afternoon because there are plenty of air-conditioned stores where you can cool off.
If I were in your situation - in a wheelchair - with 2 small children - in August (with the heat and humidity) - I would definitely consider booking at least 1 or 2 half day tours of Tokyo with a private car/driver/guide through the hotel. It's a splurge - but probably worth it if you can afford it. I am assuming that this is supposed to be a family vacation
. Robyn