Whether the trailer has good or great suspension, just like a car, airing down is the best thing to do IMO for offroad trailering. It absorbs irregularities at the tire before transferring anything especially in washboards. Minimizes hopping and rebound kicks. Helps the trailer float on top of sand. Too much suspension travel can be a liability for more lean in off-camber situations.
If the trailer has a tendency to sway, try reducing load/weight aft of the trailer axle.
If the trailer has a tendency to sway, try reducing load/weight aft of the trailer axle.