We stayed at Pop last year, November 12-20, 2014, with free dining. We had some of the same concerns. But the crowd-planning sites are VERY aware of free dining and many other factors, and it's already incorporated into the crowd calendars. So don't worry too much.
Still, free dining does have some impacts. Here was our experience in some more detail:
1. We booked FP's at midnight, 60 days + our stay. There was less availability than we expected, especially since all our MK days were party nights, with a 7 pm closing. We couldn't even get Enchanted Tales with Belle on our first MK day, unless we booked for each person separately, which would have given us a 15 minute window (not a big deal - it's a fantastic experience with young kids, but doing it once a trip is great). We got Mine Train for our second MK day, and A&E for the last day of our stay. This scared us, but it ended up working out great with fastpasses.
2. ADRs were booked, even at less popular places, right at 180 days. Every character meal except a few spots at Tusker House stayed booked virtually the entire time. We saw a bunch of openings right at 60 days (even stuff like Crystal Palace at 8:05 am), but people scarfed them up quickly, and then there were a lot of openings a day or two in advance. We had a brunch booked at Ohana, 180 days out, and we actually dropped it and picked up a better ADR time, two days in advance.
3. Pop was "almost completely booked," according to our CM when we checked in, but it honestly didn't seem that crowded, except when we walked past the cafeteria at breakfast. We brought our own breakfasts to rope drop, never ate lunch at the resort, and only did a couple of dinners at off-peak times, so the cafeteria crowds did not affect us at the resort.
4. We had one super-crowded park day, which was a Saturday at HS with morning EMH. Touring Plans and EasyWDW both had it as a "5", and it was least recommended by EasyWDW, but it fit our schedule. Touring Plans reported it as an "8" after the fact. Everything was mobbed, and TSMM was down for most of the day. I mean, even the Frozen play area had a 20-minute wait (to play in the fake snow for 10 minutes). In retrospect, we should not have gone to HS on a Saturday with EMH, and certainly not on a day that was least recommended by EasyWDW.
5. The other days were great, in terms of crowds. Rope drop was still hectic everywhere, and Peter Pan still had a 75-minute wait after lunch, but that is the reality of Disney World these days, every day of the year. (We would never wait in that 75-minute line, we just noticed it.) We had lots of walk-ons in the morning. One morning, we met Ariel as our third thing of the day, and we were only behind one family.
6. Party nights at MK are deceptively good from 5-7 pm. The park seems more crowded than earlier in the day, and it is not fun leaving the park when people are flooding in for the party, but the rides themselves are fairly empty from 5-7 pm. The posted waits were deceiving - Dumbo was posted at 10 minutes, but there were two kids playing in the entire tent, and you could get on the next ride whenever you wanted. Under the Sea was posted at 15 minutes, but it was literally a walk-on.
7. More than once, we waited longer for lunch, even eating at 11 am, than we did for any single ride on that day. We used rope drop, FP, and end-of-night for the rides with longer waits, so we only had two waits of 20 minutes or more the entire trip (weirdly, Astro Orbitor and meeting Mickey and Minnie in AK with a FP..). But in the park QS restaurants, so many people had free dining, and they took forever to order, asking what desserts and drinks qualified, etc. The worst example - it took us 40 minutes between entering Pecos Bill and getting our food, and 30 minutes of that was the line to order.
8. 4th and 5th FPs were largely not worth it, with a few exceptions. This was a combination of lack of availability, due to the early closing hours of many parks, and the generally low crowds, which meant lines were short. On various days, we used 4th/5th/6th FPs for Dumbo, Star Tours, and Seas with Nemo when they were walk-ons, anyway. But we did get additional FPs for Everest, Winnie the Pooh, and Buzz Lightyear that were very useful.
9. There were always big crowds for the buses to and from Pop, but buses came frequently, and we never failed to squeeze onto the first bus that arrived.
