My wedding is Sept 15 in Turks & Caicos and I sent out save the date emails about 4 wks ago with instructions on how to book if they were interested in attending. I just ordered my formal invitations and plan on sending them out in the 6-8wk timeframe. Do I need to include RSVP cards or include the booking information again especially seeing that I have a pretty good idea of who is planning on attending?
Actually, response cards are optional, as we are supposed to assume that our guests know how to write a formal response. And, even though it seems that most people do not, we don't have to include them. You could include some sort of contact information for your guests in case they need to confirm.
You also don't need to include any other info, but it is a nice gesture if you feel that it may be useful.