I'm doing another partial solo trip in March. Some of my best park days have been solo, though I still feel like the parks were designed to be shared (as was Walt's intent).
I did the Future World tour solo, which was nice; stopped and took in all the little details in World Showcase, like the cool train (realized they adjust the tiny details in the tiny town to reflect the season or event, like F&W); rode the steam train a little too long; rode the monorail from MK to EP and back, just for fun; rode HM and Pirates as many times in a row as possible, for no reason at all; grazed on whatever food was appealing, regardless of meal times; and even got an assisted listening device used by folks with vision problems, just so I could close my eyes and try to imagine what it's like to experience the park without the gift of sight. I did that in three parks, actually. It sounds weird, but was an enlightening experience, and a way to your the parks anew.
This next trip will probably involve riding Star Tours over and over, then watching the Muppet Show that nobody wants to go to, hopping over to Epcot just for SSE, The Land boat ride, and Figment, then maybe back onto SSE a few more times, then over to MK to wander about.
One thing I don't recommend is wandering the MK a little drunk, if you're a solo dude, and chatting people up. After spending some time at the Poly bar one night, I hopped over to the MK to try the HM a little drunkish (could mostly walk straight). That was fun, but I think I made too many new friends while walking.
Didn't think about the perception of a happy, talkative, buzzed bro wandering around a character-laden theme park alone. Crap!!! Fail. But it wasn't really a fail...it was quite fun. Those Backscratchers will sneak up on ya. Three backscratchers and a Lapu Lapu are extra-super-sneaky.