[912newbie]

So I am soon to "inherit" a '66 912 from a friend's father. I dont know too much about the car except that it's free so I didnt ask too many questions. As far as I know, the car has been on blocks for the last 15-20 years inside a mostly-covered garage. The owner states that the car ran well before he put it on blocks, but was placed in storage becasue he knew he wouldnt be driving it. Anyway, the question is, I plan on towing the car to my garage and starting by draining the fluids and replacing the battery and plugs just to see what the engine can do, but since the car has been sitting so long do I have to worry about doing some serious damage if I run the engine for too long? Should I assume that all the gaskets, hoses, belts, etc are shot? Are there any other things you all would recommend doing before attempting to start this hibernating beast? Any and all advice would be much appreciated, this is my first "vintage" car and I would rather not damage it if at all possible. Thanks so much.