Hey, Chuck!
I'm in my application process for similar volunteer opportunity (US Army Corps of Engineers/Benbrook Lake, TX) and haven't given fingerprints yet (still residing in Michigan), but signed consent forms for extensive background checks. It's my very first volunteer opportunity ... 8 years Navy ... 100% Service Connected Disabled Vet here, ... even retired from Federal Employment (VA), too.
I'm not registered with any state's sex offender list YET (just kidding of course); however, I did have a couple indiscretions (DUIs early 2000 & 2001) that will probably show up. I'm hoping that doesn't throw a wrench in the process.
If anyone knows how "extensive" and how "horrible of a person" one has to be to be denied ... feel free to comment.