First, do not even consider not making ADRs. We were there May 5-13. On 2 occasions there were signs up at guest services showing that there was NO availability for dinner (TS) at that park that day. An ADR means that you will have a place for a sit-down meal. You can change it (if available) if you desire. We changed several after we arrived at the park....but an ADR means that you will have a place to eat. You are going during
free dining--MAKE ADRs
Timing--if a park closes at 8, the last reservation is generally at 8. The parks are actually "open" after the stated closing time. In fact, if I park is listed as closing at 9, the fireworks start at 9. The busses run about 1 1/2 hours after the listed closing. The last reservation will be scheduled at a time so that you have enough time to eat comfortably before the park closes.
We also find that eating at odd hours reduces crowds and frequently gives a better experience. However, I'd still make ADRs.
As to camping vs. Value and
DDP--that's really a personal experience. As the mom, I don't like to be responsible for cooking while on vacation. We frequently do breakfast in our room, but never dinner! DDP also gives each person some flexibility--my teen would go to Disney Quest with instructions that she could use one CS meal or one snack if desired. That way, I knew that she had food available. She frequently didn't use what I told her she could "spend," but she liked the freedom. At Epcot, if she wanted CS in Japan and I wanted Fish & Chips, it was fine.