While I'm not an adult man (gal in my 30s), I had a wonderful solo experience last year at
Disneyland. I was waiting to board the Monorail at the Downtown Disney station. The driver noticed me taking my weirdo pictures of small details (like signage and architectural detail)and actually approached me. After asking me about my interest in the all the wonderful "disney details", he offered to let me ride in the cockpit! He even allowed me to take some pics in the driver seat (not in motion of course!). It really was a fantastic and magical experience that happened solely BECAUSE I was alone.