1986 Other Chevrolet Models hot start

My 1986 airstream 345 wont start once the engine is hot if we drive it for an hour and turn it off it wont start back up untill cool, we have replaced all wires going to starter I cant find a qualified mechanic near westmont il. That can help us, also we have some electrical issues with the dash, if we turn the lights on the air gauge goes out, and there is some random buzzing, ( like a warning sound) coming from under dash