We've sent/Plan to send:
A very non-official/preliminary Save The Date @ 2 years out.
Printed on tags attached to our favors at our engagement party
Newsletter #1 / Save the Date with Preliminary Response Card @ 12 months out
Why we chose Disney, a short thing about each of us and how we met, the general itinerary/calendar of events, FAQ's (do I need park tickets, can I bring the kids, etc.) Having sent the preliminary response cards out was SOOO helpful in getting a guesstimate on how many people to plan for.
The official Disney Save the Date @ 10 months out
Newsletter #2 @ 7 months out
Resort Info, how to book rooms, DME, flying vs driving vs train (pros/cons), rental cars, etc.
Newsletter #3 @ 4 months out
EMH, things to do that don't require a ticket, things to do in FL, dining/ADR's, Disney's transportation system, the parks, park tickets, photopass.
Newsletter #4 @ 1 month out
TSA requirements, reminders (make sure you booked DME, etc), bus schedule for day of the wedding, theme park tips, "Our Special Guests" (short blurb about parents/wedding party/etc), weather info, packing tips, wedding day itinerary.
Welcome Packet to be in the Welcome Bag
Itinerary/important info, what to do if you miss the bus, etc.
I know it seems like we're sending a lot of info, but for 70-80% of our guests, this is their first trip to Disney and from the initial questions/concerns we were getting before we started sending newsletters out, there were a LOT of people who were feeling overwhelmed by the notion of planning a trip to a destination wedding.
The key was to provide a short blurb of info about the given topic that provides the essentials and where to find more info if they want/need it.....not to have verbal 'throw-up' of Disney so to speak. Despite it seeming that we have a ton of info in some, we've kept each newsletter down to 2-3 pages total (using both front & back).
We've gotten nothing but positive responses and thank you's from sending our newsletters, and it's cut down considerably on how many times we are asked the same question over and over.
HTH