Having gone to WDW several times solo, I can say you will have a blast. When I went last year, I did the CP (with the dinner package -- made things alot easier) & viewed the 3D Osbourne Lights @ MGM. Some other things I would suggest would be:
1. Have dinner about 7pm at O'Hana's (make a PS though) on one of the nights for MVMCP. After that, head down to the beach. Grab either a lounge chair or hammock and relax. When I went last year, the Electrical Water Parade stopped in front of the Polynesian at 9pm, then at 9:15pm, the MVMCP fireworks went off. They start with the regular Fantasy in the Sky fireworks, then the Christmas one's. These are cool, because they are shot off in the round. The view from the Polynesian beach is perfect to view these. You may want to bring a camera or camcorder.
2. Resort hop! Make sure you make time to view all the decorations at the Deluxe resorts (except the Contemporary -- very little done there). These are amazing, especially the trees & the gingerbread displays. What I did was cover the MK resorts during a break one day, then did the EPCOT resorts on a break another day.
3. Head down to Downtown Disney Marketplace and view the decorations there. The tree next to the new toy store, had decorations in the shapes of game pieces (like Scrabble, Monopoly, etc.). I would suggest doing this during the day. I went one evening and it was PACKED!!