One item to consider in this situation: I upgraded my utility trailer to 5.30 x 12 tires to buy some extra load margin. This size should fit the same wheels as a 4.80 x 12 tire. I've got thousands miles, mostly long trips on the highway, with widely varying loads on these tires - and no problems.
In my experience, bearings aren't a problem, even for the low-end utility trailer kits. My bearings are still original from 1992 - but get re-greased regularly.
5.30 x 12 tires are a fairly cheap and easy upgrade that makes the typical low-end utility trailer kit much more capable for long trips.