I recently fantasized about doing this. I think jumping around would be a good idea to vary the experience. My idea was to do it for charity and seek multiple donors pledging an amount per show. Two shows a day would still take around 5 years.
Other idea is to do all versions of a specific song. How about the ultimate Me and My Uncle Marathon!
Second thought, Dark Star or Playin might be more interesting.
Personally I would go with a ballad, either Stella Blue or Black Peter.