Smaller tires get a bad rap about bearings. Simply not true. The faster a bearing spins, the higher its capacity, and the lower its rate of wear, up to 3600rpm. I'll leave the math to you.
The failure of bearings is much more common with small tires due to water intrusion. This is especially common with boat trailers, but can affect any trailer driven through water that reaches the oil seal.
What happens is hubs and bearings warm when spun, which warms the air inside, which causes the air to expand, which forces a bit of the air out of the oil seal and/or center cap. Then, when the hub cools, the air inside contracts, drawing air back into the hub. Unfortunately, when warm hub meeds cool water, water is drawn into the hub.
The trailer industry's solution is the spring-loaded cap, which allows the volume of air to change with temperature without air or water entering or exiting the hub. This works great, except people think pumping grease in a spring loaded hub regreases the bearings, which it does, but only by displacing air. Grease also expands and contracts with temperature, sometimes to the point and over-greased hub blows the cap completely off.
After explaining this all to my son, he fit spring loaded caps to his boat trailer, but only after replacing the grease fitting with a Schrader valve. When he gets to the boat ramp he uses a bicycle pump to make sure the spring is fully compressed in each cap. The spring provides enough pressure to keep water out of the hubs, but not enough pressure to blow grease out.
Water is the biggest killer of trailer bearings. It really doesn't take much of a puddle to splash a wave of water over a hub inside a tire on an 8-inch wheel. 3 inches of water is enough.
Overloading is the second biggest. Tires with tiny wheels usually go on hubs that have tiny bearings, some with load capacity of less than 300 pounds each. Don't overload bearings.
Third most common cause of trailer bearing trouble is neglect. I clean and repack every 10,000 miles or so, and never have had a bearing problem. The grease that came on my HF trailer bearings looked suspect. I cleaned and regreased them with a good synthetic wheel bearing grease before installing the huds. Real wheel bearing grease, not the crap you use for suspensions.
As far as little tires not holding up, overloading and underinflation are the two biggest killers.
I like the suggestion of a small utility trailer for trips to far away places. I'd shop around for hubs with the same bolt pattern as my truck and an axle to fit. Any vehicle will more easily tow more than it will carry. This might allow moving some load from the camper to the trailer, resulting in a better ride and drive quality overall.