Glider towing, parachute dropping, banner towing, photographic sorties, get your CFI and start instructing. The point is, whatever you do, do it only because you have a passion for it. If you are towing gliders, do it because you love gliding - if you don't then you will very soon get p*$$ed off with your lot.
Btw, I dont think 35 really is too old. Here we have a guy who came about 3-4 years ago age (about) 43, with minimum flight time. He is now a training captain, and soon will be a TRE. Extra years often bring maturity and dedication that a younger person may not exhibit.
RIX