The best part of a solo trip is only being responsible for yourself. If you decide to change your plans at the last minute and go to MK instead of the Studios, no big deal. If you decide you want to sleep in and stay out late, or get up early and go to bed early, no one is there complaining. If you would rather shop and take in the live shows than ride the rides, that's OK too. Sometimes on solo trips, if there's something going on that I like to watch, like the candlelight processional at Epcot, I might sit close by and listen to all three shows, without anyone getting antsy and wanting to go "do something". On my last solo trip, I was at Fort Wilderness and saw something I liked in the shop, but it wasn't in great shape, so I went to MK to look for one. Found one in MK, and thought of something at Epcot that would go great with it, so hopped on a BC bus and went to Epcot and bought that. It would have been difficult to go to so many places within about four hours if I had to be concerned about someone else's itinerary.
A lot of people express concerns about TS restaurants, but I've never felt awkward in any TS restaurant. There are so many convention attendees there alone, or significant others of attendees passing the time, that no one looks at you twice if you're there alone. I've found the CM's go out of their way to be talkative if they feel you want to talk, and they will leave you alone if they feel you want quiet time. I've never felt that I got bad service or a bad table just because I was there alone. The only disadvantage to dining alone is if the CS restaurant is really crowded, there's no way to save a table. You just have to get your food and hope for the best. If I have a table for four and see another solo trying desperately to find a table, I'll offer the empty seats.
I've taken solo trips for many years, and although I enjoy the trips I take with friends and family, I really enjoy the solo trips more. They are more relaxing and more fulfilling than the other trips. Once you do it, you'll want to do it again, and again, and again. You'll be finding excuses to go on your own, or going for the weekend without telling anyone where you're going so they don't ask to come along. It's really fun!