How about 31 count kata, 13 count kata, 20 jo suburi, 7 ken suburi for starters. With or without the weapons doesn't really matter, just let your mind imagine the waepon is there. This is great for relaxation and for sorting out breathing patterns.
Also footwork, I've seen tenkan mentioned so add in tsugayashi, irimi ashi, kaiten, irimi tenkan or whatever your dojo calls the various moves.
What about visualisation...take your organisations syllabus and work through it with an imaginary friend. (try not to talk loudly to them though
). I've always found this useful.
If all else fails a bit of shadow boxing will get your heart rate up.
Be careful though...In the same situation I thought I'd use some hotel furniture as weights..ended up pulling the legs off a chair and having to fix it with chewing gum!