[wingnut60]

A common problem on Suites fivers--the original valve cable is over-length and wound around the basement. Solution is to replace the valve/cable with a shorter length unit, and route the cable more directly to the handle location. Not a terribly hard job, just kind of tedious. Long arms will help, also need to take the water filter off to access the area.
Also, need to drain/clean the tank well, and tilt the trailer to the drain side before taking the old valve out.