I don't know about sandwiches but if he's lucky Matt Smith might get to go to Longleat again, if they reopen that Doctot Who Exhibition there!
As for the actors getting younger, here are the ages when they took on the role (as best I can figure out/steal!):
- William Hartnell - 56
Patrick Troughton - 46
Jon Pertwee - 51
Tom Baker - 40
Peter Davidson - 29
Colin Baker - 40
Sylvester McCoy - 44
Paul McGann - 37
Christopher Eccleston - 41
David Tennant - 34
Matt Smith - 26
It's a bit all over the place but the general trend has probably been down - 50s, 40s, 30s...
Hopefully Matt Smith will stay in the role for a few years, so he'll probably be knocking on 30 by that time. By then who knows who will be running the programme? The Vast Toffee (MN) will be very hard to replace but whoever it is, I very much doubt we'll get a Doctor played by someone under 26.