This rv dealer is the biggest con going. Should have paid him with a check that had ink that disappeared within the time you left after purchasing the trailer.
If the caulking can't last a few years at worst I would not buy anything from him and raise one big stink over it till he fixed it.
Warrantee should cover any leaks whatsoever within the first year other than leaving a window or vent open to the elements
2008 Cardinal 30RKLE 5th wheel sold
2006 Rockwood 2607, 2001 Traillite
55 nights 2009, 53 for 2010
44 for 2011, 38 for 2012, 35 for 2013, 51 for 2014