If you can be flexible, and are willing to eat at off times that helps. We had ADR's in June but were forever changing our plans. We were able to but often we were eating dinner at 9:00 p.m. or later or eating lunch at 3:00. I also have found the restaurants at these resorts to have availabiltiy,often last minute and they are all very good in my opinion:
SSR: Turf Club
OKW: Olivia's
CSR: Maya Grill (although if there's a convention going on this one can be full)
POR: Boatwrights
CBR: Shutters
I have also gotten last minute ADR's at Wolfgang Puck's Cafe (I walked up, and asked if they could take us in about an hour they could). And at Tokyo Dining in Epcot I was able to call in the afternoon and get an ADR for pretty much anytime I wanted that evening. Plaza Inn in the Magic Kindom is another one that often has last minute walk ups. Partly because its so reasonable it isnt' considered a good deal on the
DDP. But its very good, we love that place.
If you have a car and can get around with ease that also helps.
Character meals, O'Hana, Le Cellier, Coral Reef are all hard to come by and I would be surprised if you could get a last minute adr during
free dining let alone a walk up.
Converting ts credits to cs credits can only be done by your resort. None of the restaurants can do this. And its not a given your resort will do it.
I would advise you to make some plans in advance. Go to
www.allearsnet.com and check out the menus of all the restaurants. You can always try to change them once you get there. The bottom line: Free Dining isn't free. You paid full rack rate for your resort at a time when a deep discount (as much as 40% off of rack) could have been had. So your credits are free but your room came at a much higher rate. I wouldn't chance not having some meals in place so that your high priced room doesn't become a high priced lesson!
One way or the other, you'll have to spend time figuring this out. Either now when you have the time or in September when you may have to go up to guest services or mulitple restaurants trying to find places to eat. Which can cut into your day. Walk ups are nearly impossible at many places, esp. during free dining when restaurants are packed.