Just wanted to pass along a great product called Seal-Tite™ Corner Seal from Dicor. This past fall I bought my 1st TT, a 14 ft 2003 Sun Valley Road Runner TT.
Overall the trailer is good condition for being 13 year old, but there were some gaps in the siding at the front corner trim.
After removing corner trim & old sealant you add the tape along the corner & apply Butyl Sealant on the trim and reinstall. The tape does a great job at holding the aluminum siding together and has a exterior felt surface to adhere to the new sealant.
For the sealant I used:
Dap 27062 VOC Butyl-Flex Gutter and Flashing Sealant
Here is a link to the product and some pictures of my repairs.
Seal-Titeâ„¢ Corner Seal | Seal Design LLc| Official Website