When it comes to maintaining your RV, you are best served with preventative maintenance wherever possible.
Wheels and tires are a sticking point for many in the industry. The problem is with ST (trailer service) tires. Unlike automotive grade tires, trailer tires are patterned differently, graded differently, and constructed differently. This causes many issues for people who misuse their tires.
First, an ST tire is either a bias-ply or a radial tire, much like a car tire. There are people who swear by both, but either will serve well if maintained properly. A radial will typically offer a smoother ride and lower operating temperature, while a bias-ply will usually offer a higher load rating, all else being equal. Trailer tire load ratings are given at maximum pressure, usually around 55 psi, and are rated for a maximum speed of 65 mph. The sidewall construction on a trailer tire is also typically much stiffer to resist trailer sway and to stand up to scrubbing while turning. Many people who have problems out of their trailer tires are towing at a speed greater than 65 mph, and/or operating with a lowered tire pressure.

Tires should be closely monitored for signs of stress: cracks from aging, uneven or excessive tire wear, tread separation, road hazards, etc. In addition, tires should have an appropriate safety cushion as compared to the load they are carrying. For example, if your trailer has a 7000 lbs gross weight rating, your total tire capacity should be equal to or greater than that weight. In this case, each of four tires should have an individual weight rating of 1750 lbs or greater. Keep in mind, some of the trailer's weight will be carried by the tow vehicle, leaving an adequate safety margin when total tire capacity equals the GVWR of the trailer.

Another important feature of any good-sized camper is the braking system. There are a multitude of braking systems available from electric over hydraulic with disc brakes to the tried-and-true electro-magnetic drum brakes. Electric drum brakes are by far the most common, and the system I will discuss here.

The system is not unique to campers, and is an industry standard as far as parts and fitment is concerned. The system operates via an electromagnet. The oval metallic piece in the above photo is drawn to the back side of the brake drum when electric current is applied. As it is drawn towards the drum, it actuates a cam system attached to the brake shoes that cause the shoes to expand outward. As the voltage to the shoes increases, the shoes contact the drum increasingly tighter until wheel lockup occurs.
For a full inspection of bearings and brake/shoe adjustment,
this is an outstanding resource with photos. Keep in mind that an E-Z lube axle has a grease zerk on the end of the axle, which pushes grease into the bearings. This is great, but it's important that you do not over-lube the axle and blow out the grease seal. This will cause grease to contaminate the brake drum and shoes causing unpredictable brakes or no brakes at all.
For activation purposes, it is necessary to get a good brake controller for your vehicle. There are two types of common 12-volt controllers: Time-delayed and proportional. Time-delayed setups are exactly what they sound like. They operate the trailer's brakes after a preset amount of time, and they supply a steady voltage set by the user. This is inefficient, as you are left with either too little braking or too much braking on the trailer. A proportional controller varies the voltage given to the trailer brakes according to how hard the vehicle is braking. By using an inertial pendulum, the brake controller senses g-forces in the vehicle and operates a variable-resistance circuit to change trailer brake output from zero to the full 12volts (lockup).
I use a
Tekonsha Voyager, as it is a proportional controller that won't break the bank. The unit I have on my Chevy Tahoe is actually the third I have owned. All have given reliable service; I have regrettably left each one I had before in a vehicle I have either sold or traded. A current crowd favorite has been the
Tekonsha Prodigy P2. It costs about double what I paid for the Voyager, but offers even more precise control over the braking functions of the trailer by digitizing settings (rather than the analogue dials on the Voyager).
A properly adjusted rig will stop as short or shorter (more braking axles) than the tow vehicle alone.