Then there is the option of electric trailer brakes with hitch pressure control...I live in a hilly/mountainous area and I have towed near the edge regarding capacity. The issue of primary concern is braking rather than uphill. I've seen a lot of jackknifed boat trailers behind Tacomas and like, and some compact SUVs, usually on a downhill curve with a decreasing radius. They go into the curve too fast, brake hard, resulting in weight transfer forward. The trailer lifts and pushes the rear of the vehicle off the road, resulting in a jackknife.
This can be avoided with technique, primarily not driving down twisty mountain roads too aggressively and braking hard in the corners, opting to brake prior to entering the corner, and accelerate out of the corner. That helps greatly with weight distribution and control.