Toyota RV's. Notoriously leaky things. Ours sat outside for about a thousand years and had pretty extensive water damage. So (just about) first on our list with renovating was resealing all of our exterior corner trim.
It took a long time, multiple days of work to do all four. Needless to say we are experts at getting out rusty screws and scraping sealant now.
So if you didn't know it already... our RV has interior water damage. The cause of which is from...you guessed it....sitting outside for the last 20~ years! All the sun and rain and WEATHER left our stripes cracked, faded and FREAKIN TERRIBLE. (Not only that but our fiberglass siding is powdery & oxidized. Read til' the end for details on that.)