Have the present Doctor regenerate into an aged version of one of his past incarnations, get the companions to do all the running around and just let Tom be Tom.
Nobody does it better.
Although I wouldn't trust today's production team to give him any decent material to work with.
Bringing Rose back should never, ever happen IMO, she left the show twice and doesn't need to return again although I expect the RTD crowd to be dragged back for the 50th Anniversary and all the Classic era characters will promptly be shoved into the background....it is the way of things
I don't wish to have a go at fans of the 10th Doctor & Rose in general but it does seem to me like some can't seem to accept the show is about change and only want the show with those characters, hence all the threads on numerous fansites where people come up with different ideas to bring them back.
"I'm not a human being........I'm a Time Lord. I walk in eternity"