I just bought some new backpacking gear, and am eager to try it out.
Arches is my favorite desert park. For some outstanding mountain backpacking, the Naturalist Basin in the high Uintas is amazing... snow melts by July so you can hike in, absolutely beautiful high country - many lakes around 10,000 ft. It's an awesome place. Do a google. If you don't want to hike in, check out Mirror or Moon lakes, also in the same general area. Oh, and yes, you can pack a rifle or sidearm, it's nat'l forest, not park.