I replaced bearings in boat trailer with Timken in 1990 American made but not long after they went to China.
Take the drums off and take them to a parts store, that can handle it, most may not anymore or machine shop and have the races pressed out new ones in and rear seal and front. I have removed them, and you can buy tools that fit. I used big sockets from wrench set chisels, and big hammers, not easy for me to do anymore. Check the magnets and condition of brake shoes and wiring. Wiring on trailers that sit for a while are an usual target for rats and squirrels. When you buy bearing sets, the only way, they come with races.
Don't know who makes bearings today in the US. If the bearing shells and races aren't perfect don't buy them, The Chinese I took off that trailer had gaps in the races and the bearings themselves were cracked and flaking.
Peace of mind, you may won't to put new brakes and backing plates on the trailer, not expensive or use to not be, and may be needed, and the wiring if bad at any one point buy heavier wire and rewire the whole breaking system.
Check the spring hangers and rubber bushings. Most likely the rubber bushings are toast, but hopefully not. And if not equipped with shocks kits that bolt in or on and shocks don't cost that much. They might keep your dishes from flying out of the cabinets and into the floor. I hope you get a lot of enjoyment out of the trailer and RVing.