We're going to stay with friends in London this weekend, and what to do some touristy stuff. DH and DD have never been to London and I haven't been for years, so even though we KNOW it's mad we're not going to have another opportunity like this any time soon so will have to just go with it 
Sooooo, what is achievable? We will have all day Friday, Saturday morning (have tickets to see Hetty Feather at the Rose in Kingston Saturday pm), and much of Sunday at our disposal.
We would love to do Tower of London but it's really pricey. Friend lives in SW16 so we'll be getting the train into town - will this ticket get us the 2for1 Tower tickets? Would also love to go to the British Museum, would it be best to do this on Sunday? I'd love to see the Viking exhibition and there are more free slots on Sunday for this. Other things we'd like to do/see - Thames, Big Ben, Harrods, maybe Bucks Palace, Natural History Museum.
Are we insane? Will it be hideously busy everywhere? Especially the museums?
Tia 