There isn't an "official" FJ summit in Moab. However there are groups that decide to go on their own both before and after summit.
is in the know and might be able to shed some light.
Also there are other Toyota based events like Rock Therapy in Moab too.
There's no registration for "Moab Before Summit" - people just gather in a parking lot and decide on trails, groups etc on each day, usually the Saturday, Sunday and Monday before summit. There is also a similarly named thread
always posts details on. As well as doing a great job managing the logistics, he is also a legendary trail leader
And even if you don't do one of the official runs, it's always fun to be in Moab before and after summit as you'll be seeing FJs crawling around everywhere, enhancing your every photograph
Rock Therapy, a Toyota event of mostly Tacos, was just changed from spring to October and their registration recently opened. I know the organizers and hope to attend one day. They tend to do the most difficult trails possible and even rank them for recommended tire size.
Moab after summit is on your own but I ran into a few cool people crawling around. Probably wouldn't be too difficult to pick up a run.