We were able to schedule a tentative date a year before our desired wedding date, but you don't go into a contract/planning mode until about 8 months before your wedding. While it seems like not enough time, since that is all they do, and there is not a debate of if a caterer, DJ or something is available (within Disney - outside vendors are another story) you will probably find you have plenty of time.
We did a site visit and picked dates at one year out, but never did any further visits until the week of our wedding. I planned our entire wedding over the phone in less than 10 phone sessions. It was wonderfully organized (thanks to a great EM) who said "next week we'll do food" and so I got with DH and my parents, reviewed all the menu stuff, then did the meeting, and in the first couple minutes of our next call I gave our final plan (unless I already knew). Before I knew it the whole thing was planned.
