a new roof can make life ez for you cut and weld or you may think about a chop job dents are not to bad to pump up with a port a power try going to your local library and look for some very old body books there a art to pumping up roof and the old body men fixed more bent metal then now .you would be shock what you can fix .getting the metal to unlock is the trick i would build a place on the floor to push off of with wood blocks .its better to work in small steps i pump up more then one roof .but if a big tree the body and body mount could be crush in and the body if you look at it from the side look like this ( ) this can be fix to by pulling in the body with come a long or rachet chain fall then if door surroundes can be push and pulled by by putting a port a power in the door jam like this \ or / and can be suck in if needed with a come a long and some body clamps and lots of wood blocks help and you can make pull hooks or weld pull tabs on were you need to pull and cut off when done you can build hook s for the job just make sure there thick like 1/4 or 3/8 steel you do not want one busting and come loose and hitting you