Goodness, so many replies! Going to print out this thread to ensure I miss none of your fantastic suggestions. GrannySomerset, I too grew up in York, and yes, very good point about how much walking is involved - we shall have to pace ourselves. Elliane, thanks again for suggesting bright caps and mobile numbers in back packs.
You're all right, I really must plan this out so carefully, and I had no idea that you had to book places at museums.
This Gran is going to be spending much time on the computer in the next couple of weeks!
So pleased that I asked the question - any more suggestions very welcome, all will be so very much appreciated and considered carefully
Thanks again