Camper Repair-Big Rebuild

So the camper is drying out. I will be replacing wood around the top and bottom corners, and a significant part of the floor. I will be cleaning and sealing the seams on the roof soon, it has been raining frequently. As I replace the wood inside along the seam I need to cut off old rusted staples and screws so it fits flush. However I want the seam to stay tight. I'm trying to figure out the best method for this. Should this be a two step process- replace screws as i install wood, then after inside is put back together and camper is structurally strong again I can remove the corner seam cover and staple and caulk and re screw. Or just replace screws and caulk the edges of the corner seam cover.