Honestly, I don't think there's much you can do. Time, desire, and ability. Remove any one of those things and you won't/can't be able to get out there and help.
For me, the course is just under an hour away. Add up the drive to and from and I'm looking at 2 hours of wheel time to go work for free. (Gas for my pickup isn't cheap either.) Add the fact that the weekends are really the only time my wife and I are able to spend time together and it's a double whammy. I rarely even play disc golf on weekends, let alone getting out and building a course. I can only imagine how little time someone with kids would have.
Some people honestly just don't have the ability to do that kind of manual labor, especially in the heat of the summer.
My brother in law and I, along with two other friends did go up there about a month ago and completely cleared hole one of all the debris, and put a pretty good hurting on all the debris on hole 11. I love helping, and I hope to get up there at least one more time, maybe two, but I can't make any promises.
I assume most people are in similar situations.