Combining the ideas of a few brides I think I am going to do this:
Send Save the Dates (luggage tags)directing everyone to my website with Unofficial pricing, accommodations, etc with a Pre-RSVP (post card) so I can plan OOTs, dinner, tables, centerpieces, extra- we are having the reception down there with no AHR. 1 year out.
Then send a Newletter Titled Our Names Wedding- YOU'RE INVITED! so there isn't confusion...this is your invite. With finalize pricing, down payments due dates, extra...(all this information will come from my website. But what it seems is people either don't go on the website or don't get serious until they get a paper invite. I will send this out pretty early too prob 9 months so that guests can space out payments on the trip and we again can finalize details.
I hope this works!