Junky

I am new to this forum so let me kniw if I am doing something wrong. I bought a 1978 d150 a year ago. Dicumented 1 owner with 66,000 miles. Need a lot of tlc because it sat in a garage since 96. i have ut running grwat. Valve seaks, hoses, belts, fuel pump, etc, etc, etc.
I am down to AC. Put on a reman compressir, dryer, expansion valve, fixed some wiring only to find a leak in tge evap coevapnd I can't locate one. Any sources out there anyone can share?
Thanks
Junky