I have a 2009 Greyhawk 31GS that has the dump valves in a very difficult location to pull the handles. They are both under the coach about 12 to 18inches to reach them. Its a on the hands and knees job to pull the handles. I have always tolerated getting the job done, however with the need to have two new knees installed I am looking for a remedy to make this an easier job.
Are your pulls on a solid rod? Or do you have a cable?
If you have a solid rod, and it pulls out in a good direction. you can replace the rod with a longer rod. You will need to add a support, but that is easy.
I took an old awning pull rod and added the outer "fingers". I just slip it over the t-handle and can pull it open AND push it closed. I've got 3 dump valve handles under my trailer which I can get to without it, as long as the slides are closed. It comes in handy when at a full hook up site and need to dump tanks. Sorry the first pic is sideways, but you'll get the idea.