Best london bus tour for me and dd to see the Queen?

[knackeredmother]

dd (4) has just announced she wants to have a sleepover with the Queen! I thought sod it I will take her to London on Friday to see Buckingham palace and other London sights. I'm trying to make the most of our time together before she starts full time school in September :(
I think one of the bus/boat trips where you can hop on and off would be best. I would be grateful for recommendations for any?
Also a good but cheap Japanese/sushi restaurant (not yo sushi) as it is dd favorite .
Any other tips for a good day out in London with a 4 year old gratefully received. Thanks in advance!

Why don't you take the train out to Windsor, to see the queens real big castle (that looks much more like a castle!!) Its a nice place to visit ( a little pricey to get in, but the dollshouse is worth the effort!) Windsor castle is smack bang in the middle of Windsor, shops and restaurants and tearooms galore, its a nice place for a stroll, and we have a sightseeing bus that can take you to Windsor farm shop where you can buy and eat the queens produce (again very pricey but a nice place) so there is plenty to tickle DD's imagination. You migth even spot the royals!

Good idea Mummypig however I really wanted to sneak in a visit to the Science museum too ( I loved it there when I was younger!)
I'm just not sure if a day travel pass would be cheaper and easier for dotting around lOndon.

The %2311 bus goes from Liverpool St to Chelsea and is fab for sightseeing. Sit on top deck (grab the front if you get on at the start of route) and go past St Paul's, Strand, Whitehall, Big Ben, etc. take some sarnies and make and event of it!

Sorry, NUMBER 11