I have a 232SS, and at the time we bought it, the sales person said that while he would normally caution people about going on the roof, I'm 140 lbs, so he said it would be no problem for me to get up there.
With that said- if you do go up there, I would crawl, as that will at least spread the weight distribution out. In order to inspect some of the vent seals, I would almost think you would have to be on the roof to get all sides inspected.
Look at your manual and see what it states, better to be safe that sorry, there is 70pds between what txhobo stated and you stated. Beside that he made the comment his salesman stated would not be any problem at 140, but 210 you may be just pushing it to the point of a expensive roof repair ...
Again there is a reason why they didn't put/attach a ladder on your trailer, it's so you wouldn't go up there and damage it
G384RLT The Palace Ford F350 CC LB DW 4x4 [br]Amateur Radio call W5KAV