Price your tickets carefully. You may well find the after 4 deals aren't that great. We just ordered normal tickets from
Undercover tourist. Of course, if your sponsoring group is underwriting a substantial portion of the ticket price, then the after 4's may be a good deal. (These are advertised to the group promoters to help insure attendees don't go to the park "early".)
We stayed a few days after a CSR convention. I booked a nice room at POR. We didn't have any problems doing a split stay, and, for us, it was nice to separate work from vacation. It was a MUCH shorter walk from our room at POR to the bus, than from our room at CSR to the bus stop.
You may want to make a few lunch ADR's for yourself. Make sure you make any ADR's you may want for after the convention. We made an ADR for Maya Grill for our first night, during the convention-timed it so we weren't rushed on arrival. My DH never knew when he'd be off, so we had to catch as catch can for dinners. If you think you might want last minute ADR's keep the Disney Dine# handy. When we were at CSR, the little grocery/sandwich place was perpetually lacking stock. I realized the store at AKL had a great selection, so when we needed something, I picked up a few things there. It's not hard to take the bus, or if you want to take a taxi, it's a quick ride from CSR to AKL.
Cell phones were great-if DH was really late, he could call, and if he was getting out early, he could call, too. There was a day he got done at 2pm, so we were off to the park.
Hope this is of some help!