Okay, that helps Bonnie... now the bad news. It's VERY doubtful your 1977 Scamp
was built to hold the weight
of a roof top A/C. Prior to the big Scamp
plant fire in January 2006, trailers had to be ordered to support the weight
. If it wasn't... and probably wasn't, you can't put roof air on top or it will bring the roof down! You can retro fit, by adding braces (either on the outside or interior) that go from the floor across the ceil and to the other side (if done on the interior). Most don't want to go to that extreme unless removing everything from the inside.
Your best bet would be a removable window A/C or an A/C in the closet vented to the outside... or.... all have been accomplished successfully by owners.
Pulling and resealing windows
is easy. Just takes time, a little $$ and once you do it, you'll wonder why you wanted to pay someone!