Dave,
The big issue with the brakes seems to be the cables, once they are seized the brakes rub destroying the shoes (expensive) and overheating the bearings. Remove the cables, hang them up in the garage and fill the little cups with oil which will run through the cables keeping them like new. The cables are quite cheap so renew them if they get stiff. There should be a hole in the back of the brake to allow you to flush with fresh water then leave the handbrake off. I would give the hitch a good (pressure) wash and then lots of grease. Once a year strip the hubs and lightly copper grease the moving parts.
Phill