Sight unseen? Yer scarin' me to death! Unless they were almost giving it away, someone I trusted or a surveyor would have to give me an evaluation. I 'Spose if the boat was simple and hasn't been drilled full of holes it would give me some confidence.
Ask when the last time the engine was used, how many hours, maintainance, ect. Inquire about the other systems, leaks, general condition. Determine what gear it comes with. The trailer is a whole other can of worms.
When we were shopping for a C-Dory we found what seemed to be the perfect one. The pictures all looked good and it was loaded. Only close personal inspection revealed the ugly truth. C-Dory had built a good boat but the owner(s) had botched it with shoddy installations. There were sloppy, unsealed mounting holes everywhere. The wiring, and there was a lot, was the worst mess I've ever seen. Not only would It be a nightmare to troubleshoot but it was a fire danger.