I have traveled to WDW on solo vacations several times -- and am actually doing this again next week! You can read some of my previous posts about WDW alone
HERE,
HERE,
HERE, and
HERE. Other panelists give tips
HERE and
HERE.
My biggest tip for traveling alone to Disney is to make the trip about what YOU want to do. Do you want to go on the roller coasters but your kids are too small? Do you want time at a spa, but the family usually has you occupied? Since the trip is about you, this is the perfect opportunity to have the exact vacation you've always wanted. Plus, it is very easy to get LOTS accomplished at WDW when you're not worried about stopping to tie shoes and whether someone else is hungry.
If you think you'll be lonely after a bit, you could arrange for a group activity. I loved taking the Backstage Magic tour during a solo trip. This was interesting all on its own, but it also gave me a built-in group of people to talk to. Everyone on the tour was very pleasant, and there were a few other women in their 30s and 40s who were on the tour alone too.
So, go ahead and see what you want, sleep when you want, eat when you want, and have a GREAT time.