I used to have a '74 holiday rambler... i know you didn't ask about this but the fiberglass guard for the front window looked similarly rough... i used a medium to light brown spray paint (4-5 light coats)...it looked brand new and seemed to hold up very well... it did seem that the dry fiberglass really sucked in a lot of that paint but i was very pleased with how it held up and turned out. if it has the galvanized pressure tank for the water, that would be one of the first things i'd replace (lol... literally it was one of the first things i did replace) with a plastic tank and an on demand pump... good luck!
