I have a motorhome that has a short wheelbase (182") and long rear overhang (132") and have put hellwig sway bars, blistering hd shocks, a blue Ox track bar on it and had it aligned with 5 deg. caster to improve the handling. It handles great with out the toad but still has a little oversteer with my toad. I did not feel the sway bars made a big difference. One other thing that I did while I was testing is that I increased the amount lift on my rear helper springs. That made the motorhome ride harsher but increased the stability. If you have the air shocks option, you might try increasing the pressure.
Mike