Well... trailer place was more than fair and apologetic. Turns out they didn't replace bearings back in January, just 'inspected' and repacked.
They gave me a new trailing arm, inspected hub and found it OK, pushed out the inner races, seated new bearings for $100 (basically parts half off and free labor).
We spent 2 hours trying to get the new trailing arm on the axle, but the axle was 1.75in and the opening on the trailing arm was 1.68in. Hammered a chisel to pry it open several times without success.
Gave up, took the trailing arm to another friend with a hydraulic press and pressed the opening more, left a chisel in the opening to get it pried open, and then we were able to get the new spindle back on the axle with a lot more elbow grease.
Jacked up the other side, and found about 3/16 in slop in the wheel. Pulled the wheel and found the bearing buddy detached from the hub. Red Lithium grease used at the shop was brown with evidence water had gotten into the hub. Pulled the hub and beat out the bearings and seal, found the bearings to have slop and a couple were scored and scraping.... good grief, the other hub was likely going to fail in the next hundred miles or so.
Didn't have a socket large enough to fit over the new inner bearing to knock it back in, so going to have to go back to my other buddy with the hydraulic press to seat the new bearings. Hopefully have the hub reinstalled, packed, and tire mounted tomorrow so I can get the boat back to my house and wash it