If your trailer suspension is leaf springs and the axle perch is on top of the springs, there is a common mod called an axle flip that will add 2-3 inches or clearance.
If your axles are springs are already below the springs it should be a fairly simple matter to have a spacer made.
We had our torsion axle travel trailer lifted recently with the help of a kit supplied by Forest River and a local suspension shop. See
Mods - Trailer lift.