Trailer bearings, yes, once a season seems to work. Depending on how much towing is done throughout the year. Along with your trailer lights and wiring. Just a visual. Impeller, impeller, impeller oh, and the impeller. Kinda like a buzz kill if it's not working correctly. Parents had a Centurion that they let slip on this. Broke the pump shaft in theirs. Just a visual inspection of your ignition. Plugs, wires, cap, rotor. I found mine had significant corrosion under the cap. Never know the maintenance routine of the previous owner. Oil and filter. Batteries. I highly recommend an on board charger/maintainer. Just keep it plugged in, and your batteries stay hot. Not sure on the shaft seal and or stuffing box on that year model.
Rodney
2007 21V - Trailer bunks-*Done