Do all pumps, stereo, PP etc work correctly? Also, what kind of shape is the trailer in? If it is in salt water, the the salt can eat it from the inside out. Was the boat on a lift or taken out of the water every time and stored on the trailer? I am assuming it was stored outside bc of the shape of the cover.
If it were me, I would say between 30-35K, but not more than that, assuming all the work that has to potentially be done. Salt water can really take a toll. Did you notice any pitting in the tower at all?