Ouch! Tires 23 to 24 years old. I'm surprised they are holding air. I would replace the tires before putting the trailer on the road.
As to bearings and brakes, it is time to pull the hubs and do a good inspection. Likely lots of rust in and on the brake parts. Depending on the rust on the hubs where the brake linings contact, they may be able to be turned, depending on the rust pitting.
You will need to do a good inspection of the wiring associated with brakes, turn signal lights, and brake lights. Do a temporary fix on the system that doesn't work to make it road-worthy.
All of this depends on how far you have to travel. Even then, at a very conservative speed.
Bob