Re: chaperral
Ok, what kinda of 24' Chaparral is it? A cuddy cabin? A cabin cruiser? Specifically, what model number? Why were the heads done last year? How many hours are on the engine? What condition is the vinyl seat covering in? You say "excellent", does that mean you have been on this boat? What does the bimini top and camper canvas (if they are there) look like.
In 1995 Chaparral still used wood floors. So you would want to walk around and generally check it for signs of rot. If the boat was left uncovered and got a lot of water in it, that can lead to the floor getting "soft". Especially check right in front of the engine cover, along the sides of the engine cover, and where the motor is bolted in.
How and where was the boat used? How and where would you use it?
Regarding fuel, if it's a 24' bowrider or cuddy with a 5.7, you could expect it to get no more than 3mpg at a nice 30mph cruising speed. If it's a 24' cabin cruiser with that engine, figure 2 to 2.5mpg.