One thing I recall from my days of hauling a sail boat around is seeing a lot of trailers broken down on the road side. Some were missing a wheel.
Since I was backing down boat ramps, I installed some bearing buddies.
http://www.etrailer.com/tv_demo_bear...ddy_1980A.aspx
I recommend these for all small trailers, not just for boats.
To be safe, you should buy a small grease gun to take on your road trip..