Spray cans on the frame are ok, I've done it before when money was an issue.
I do think that sandpaper on the rims is a bad idea.
Extra fine steel wool and wd40 will do a good job of cleaning up the rust.
Better to go ahead and take the wheels apart first. That gives you a good shot at cleaning up the rims.
Spokes can be cleaned up with wd40 and a rag. Don't use an abrasive on those zinc plated spokes.
Clean the rims afterwards with de-greasing solvent, and paint the areas that were rusted with phosphoric acid to neutralise any remaining traces of rust.
Re-assemble the wheels, and take them to a shop to have the spokes tightend and the rims trued. It's worth the expense and time.
(see you in a couple of weeks, Sttg?)