A few things I have learned in pulling heavy loads that I can share with you:
Wheel bearings should be hand packed by removing the wheel and inspecting everything. New seals are in order when you do this. Do not use a grease gun and pump massive amounts of grease into the zerk fitting......it will end up on your brake shoes.
If there is grease on the brake shoes, replace them. It cannot all be cleaned off with a solvent....
Don't ride the brakes going downhill. Get on them to bleed off some speed and then coast and cool the brakes. Use lower gears.
When pulling up steep grades, don't arrive at the top and pull over to cool things off. The heat you have generated going up must be dissipated by keeping the engine running and the transmission in gear or at least in neutral. Some transmissions do not pump fluid through the cooler in Park....It's always a good idea to continue driving a few miles to let it cool down before stopping but if you can't just keep the motor running at a fast idle in neutral.
Tires on trailers are a big consideration. All of them until recently were made in China and cannot take much abuse. Folks call them China bombs because they blow. Even if they look good with great tread depth you should look at the code on the sidewall of the tire and determine manufacturing date, if over 5 years replace them!!!!!! Age matters more than tread depth. Also tire pressure should be at the recommended pressure stated on the sidewall.
Good maintenance and knowledge of what to prepare for will ensure you of a safe enjoyable trip