We were at WDW end of May and there were designated pin trading boards set up in each park and at Disney Springs. Wasn't able to trade with CM yet. The best board, by far, was the one in Epcot outside of Pin Traders. But when we were there, that location was only open 2-5pm and it also had a pretty nice line. Echoing what was said above about there being limited boards, they are mostly scrapper pins, and given all the WDW changes happening it could be totally different by the time you arrive in two days. My kids are both young so they didn't care if a pin was a scrapper pin - they just got excited when they saw characters they liked. It was still fun for them! Just not the same experience as before. We did find a few hidden Mickey pins.
We were also told all the resort gift shops had pin trading, but of the ones we tried: AK did, Contemporary did, and Wilderness Lodge did not. The boards were not on display at the gift shops. We asked for them and they brought them out from under the counter.
Have fun!