London isn't the best of cities accessibility wise, so if you have other big cities near you (depending on where you live obviously) I'd recommend trying them first lol. Not to put your off though as London has so many things to do!
If your planning on staying overnight, which by your post I'm guessing you are, I'd book the hotel first, seems the most logical way of doing it right? That's the only thing I can't really help you with, as I have never stayed in London overnight. I'm sure there is a thread about London hotels if you have a search. I would suggest the best way to guarantee you having no accessibility issues would be to phone hotels, then you can talk to a human and be sure of what your booking.
I would then book travel arrangements, as you will get cheaper tickets the further in advance you book the tickets. The cheapest site for that is www.thetrainline.com. Once your in London, you have the choice of 1 line on the Underground, that is the Jubilee line, the rest have the odd accessible station, but not worth trying to work out your route to be honest. The second is the DLR, that can be caught from stations off the Jubilee line, and is shown on the Underground map. (and it has no driver, so you can sit at the front and pretend your driving HA!) Your third choice is buses, all the buses are accessible, but you will have to plan a route, or ask people on your way round. Last option is obviously taxis, but they are EXPENSIVE!!
Underground map here:
http://www.tfl.gov.uk/assets/downloads/ste...e-guide-map.pdf
Regarding things to do, the list is pretty huge!
- London Eye.
- London Aquarium.
- Numerous art galleries (one on South Bank in between the Eye and Aquarium. 10 minute walk/ roll from Waterloo station (Jubilee Line))
- O2 Arena, concerts etc (North Greenwich station (Jubilee line))
- Couple of the tour buses are accessible, only bottom floor obviously.
- Oxford Street for shopping (Need a bus for that one)
- Buckingham Palace is within walking/ rolling distance from Embankment Station (Jubilee line)
- South Bank always has street performers at the weekends, free and pretty enjoyable!
The list goes on, that's all I can think of at the moment!
Hope that helps.
Chaz.