I've stayed at Stovall's as a solo female traveler, and felt safe the whole way. It's a really easy walk! You walk out of your room, and to the stoplight to the right (east) (that's about 2 minutes). Cross north. You're now on
Disneyland property. Keep walking north; pass Paradise Pier Hotel, and take a left (like 6 minutes). Turn right at the traffic circle (or just follow the crowds) (about 4 minutes). You'll end up right in front of security. Then you turn right, and walk the length of Downtown Disney (maybe 6 minutes). I don't think I'm especially fast or slow with my walking. What gives me comfort is knowing that Disney has 185,481,754,222,812 cameras, give or take. If anything concerning happens, Disney has it on camera. The walk way is well lit without being obnoxiously bright.
As far as Stovall's itself, they may offer you options of where you want your room to be. If you plan on using the pools/hot tubs, I'd recommend the eastern building on the eastern side. I stayed at the taller (western) building. I felt perfectly safe, but there's a hallway I had to walk through to get to the pools and hot tubs. I couldn't see what was at the other end of the hallway; if someone nefarious was hiding at the opening on the other side of the hallway, I would have had no idea. Also, there's 2 pools and 2 hot tubs. When I was there, a couple was, ahem, "canoodling" in the first hot tub, which meant I got the back hot tub. The back hot tub is around the corner of their pool building, and the lightening leaves a LOT to be desired. It felt a little too deserted for me, and I ended up only staying a few minutes because I felt vulnerable in the dark by myself.
Apart from the pool area, I felt perfectly safe and comfortable walking around the property and to/from the parks.