I've been to WDW solo about 7 times and safety hasn't been a problem for me, especially since my first time. I checked in for my first solo trip at 1:30am. Bell Services offered to escort me to my room, but I wanted to prove I could do it myself, so I declined. Then, as I walked the grounds of POR, trying to find my room, I started feeling spooked and started really giving myself H*** for being so proud/stupid for having declined the offer. Suddenly I heard whispered giggling around the corner and really got scared. Then here they came....2 women in gowns and Mickey Ears!
Actually, once, I did feel a little uncomfortable-I had a first floor room, facing the parking lot, with lots of vegetation around. But when I went back to the desk, the CM was extremely nice and understanding about moving me. Since then, I always request an upper floor room. And with so many people around (well, not at 1:30am), I never feel alone.