As we have ~1350 pin weight empty in the 290RLT, it does help to make sure that is taken into account loading, so as not put too much weight aft of the wheels. As you know, the fridge, sofa and a lot of 'heavy' storage is at or aft of the trailer wheels...
Our 290 came with the "TrailAire" roto-flex rubberized pin box, and yes it does flex enough to smooth out the ride over Railway Xings, overpasses, and roller-coaster concrete like that found west of Oklahoma City on I-40.
I dropped my speed down a tad over those kinds of 'speed bumps' and that helped also.
I also run with Firestone air bags and they keep things fairly firm over the rear axle.
Jim & Kathy
2012 Crusader 290RLT TE, TrailAir flex pin: 2012 Toyota Tundra 5.7 SR5 Dbl cab 4X2 Tow, 4.30 gears, RideRite air, TRD cold-air induction & dual exhaust: Reese 16K Slider: TST tpms
Miles towed to date: 18,950 Nights camped 192