Kim, your best safety bet is to camp where no other human has gone before (j/k). Animals typically will leave you alone. I've backpacked and camped solo a bunch (I'm a woman) and the further I get away from people, the safer I feel, and I'm not at all the paranoid nor the antisocial type. I'm a light sleeper and prefer total quiet, and I always pitch my tent where it's hard or impossible to see from a trail (I've been known to lose a tent here and there - not really, but almost). The only problem I've had in years of solo camping/packing was one July 4th weekend when I camped at the foot of Wetterhorn Pass at 11,000 feet and woke up in the night with a hypoxia attack and irrationally wanted to pack up and hike out in the dark. I finally pulled myself together and went back to sleep, but if I hadn't, there was no safety net, which you do have when camping with others. I do carry bear spray, but I've never had a critter or person threaten me in any manner - probably because I seldom see anyone else and critters usually run. It's getting harder to do, but just pitch your tent in a thicket or behind a big rock where no one even knows you're there. Just don't ever get lost, cause they'll never find you (unless you carry a PLB, which I do).
I used to carry a .22 pistol, but finally gave it away, as I felt it was more of a liability than a help, especially when I wanted to go into Canada and had to figure out what to do with it. I love going solo. I've experienced things I would never have seen when with others, like the time I rounded a corner and came upon a coyote ahead of me on the trail. I walked behind it for a good 50 feet before it became aware of me and bolted. I could've reached out and grabbed its beautiful bushy tail. Or like the time I was in Drowned Hole Draw and saw desert bighorn playing. One tip - I've found that sleeping in a tent with a mesh top really reduces any night fears, as you can star gaze and appreciate where you are instead of being in a sort of black hole.
