We just went during the free dining but didn't use it ourselves. We were so worried that the restaurants would be crowded we made ADRs for EVERY meal. It was SO unnecessary!! After the second day we cancelled all our ADRs because we found the restaurants were relatively empty and we could just do walk-ups when we truly wanted to eat, not when we had the reservations.
Free dining may have increased attendance slightly, but since it's low season, it's still quite empty. We walked on everything at all the parks except Soarin' (15 minutes) and Test Track (10 minutes).