The windshield will be a hard find. You may get lucky and someone will come along with one, but it is probably they hardest part to replace on the entire boat.
That top speed sounds a bit high but is in the ballpark.
The bottom is all fiberglass. You are correct on the stringers, they are fiberglass wrapped wood. The floor is probably also fiberglass or resin covered plywood too.
Pictures are a must. You will be amazed at what people will pick up on.
1996 Prostar 205 LT-1