It depends where you travel, how you ride and how much you carry. You currently have 200 lb of yourself plus 30 lb of bike plus 25 lb of gear (assuming you split evenly front/rear) on the rear wheel, which means a total of 255 lb.
Last Summer, I toured with a trek 520, with 80 lb (bike + gear) plus 100 lb (me) plus 10 lb (daughter) on the rear wheel, for a total of 190 lb, and had no problems with my wheels. In fact, the rear wheel has stayed true and in good shape for about 16 000 km, in spite of our numerous potholes, cracks... Then the rim tore apart and I had to replace it. Hub is LX 36-spokes and rim was Borntrager off-centre rim.
There also are sports tandem teams that ride with 36-spokes wheels.
So definitely, a well built wheel would work fine. Especially if you lift your butt on bad bumps, if you pedal smoothly and don't stand up and throw the bike on each side when climbing.