Actually.. without photos, its hard to say. If the body is solid (rear quarters not rusting out, wheel wells intact, etc.. ) its a good candidate for a 1j or 2j swap.. but probably not for you because your getting tired of dumping money into it.
I would say part it out if you got the time and sell the shell. NA's are not fabulous movers for the younger crowd because they want the "bling" of the Turbo... however, not many of them have the $$ or skills to do the swap. If you find someone who is familiar with and loves the car, your set.. however.. it can be a waiting game.
2 things kill you when it comes to selling these cars (that I have noticed). 1 = crappy photos.. people lose interest quickly... and 2 = crappy description/records of the car. I have never had a Supra (NA or Turbo) for sale longer than 3 weeks because I used a fair pricing, good description and a ton of photos. The buyers have other cars to look at... so you have to grab them.
Very hard to give an opinion without knowing the whole story of the car and current condition.