I visited WDW solo in June. I made some ADRs for the few times I wanted to do TS.
One was for lunch at the Rose and Crown at Epcot. The evening before I decided to visit Epcot as it was raining and I thought the crowds might be lighter (they were). As I was passing by the R&C, I stopped to ask about being seated. The hostess was telling the people in front of me there was no space and I didn't have any real expectations, but thought I'd ask anyway.
As it turned out, there was a table for ONE available. It was a table with one chair by the fireplace and quite adequate. II received lots of attention from many of the CM who noticed I was dining alone. Two tables over was Peter Mayhew, who played Chewbacca in the Star Wars movies.
The hostess said they would cancel my lunch the next day (at my request) but to be safe, I called in the next morning to verify the ADR had been cancelled.
In short, make ADRs if you can, but don't hesitate to do a walk-up. You've nothing to lose.