Is there a definitive thread on trim to use?

I've been doing some searching, but can't find discussions about the appropriate trims to use around the perimeter of my trailer (where the walls meet the roof). I'm also building my own entry door and doing "barn doors" to reach my galley and could use some help on the appropriate edge wrap on the edges of my doors and what type of gaskets/seals I should use to keep my doors from leaking. Any suggestions?
Thanks in advance!
Thanks in advance!