The Main was great, but very different with the smoke. The smoke settled every morning and was dense until the afternoons, when it lifted and we had blue skies. Nobody in our group was bothered by it, but I wouldn't take someone with bad asthma up there.
Our quick stop to check in with the ranger at North Fork was the only delay we had related to the fire. Inciweb.org has a lot of info on the Mustang complex fire. It seemed to be moving northeast towards Montana.
The water was relatively warm, the beaches were huge, and the weather was perfect other than the smoke. We only saw a couple other groups the whole time. I would do it again in a heartbeat.