Exterior walls only are load bearing. Roof trusses are used so any interior walls are not load bearing and can be moved. If the rubber roof is intact, then a coating can be used. The rubber roof is manufactured by Dicor, and any coating must be compatible or damage may be done to the membrane, the glue holding the membrane to the roof decking, and/or the coating will just peel off. Th gutter system is just screwed into the side. Simply unscrew and peel off.
Those FEMA trailers were built like most any RV but many had residential refrigerators and toilets and no holding tanks. Many were ultimately purchased at a great price with little needed to fix up. You may well have a good trailer at a great price.
