Good Luck on your first trip!
We had our Tradewind out severa times this year, but every time the weather went berserk as well. Went to the beach locally in January, then to Pismo, then back to the local beach, but everytime it got chilly and we also got a few rainstorms for good measure.....well, now I know our trailer has no leaks. No snow, though, thank God.
The holding tanks are tiny by comparison to modern trailers, our black tank is good for 2-3 days, and the added on grey tank is good for about 1-2 days if we're concious about using water. We simply prefer hookup sites, or go to places wher we can drain the grey water in the ground under the trailer.
It is kind of nice to have the tanks for overnighting, or while travelling and going to rest stops.
Are you going to the Rally in New Mexico?