I agree with everyone - send them out as soon as you have them done.
RSVP deadline can depend on when the resort needs to have a final count. You may also want to factor in when you personally need to know for things such as OOT bags, programs (if you're having any), favors, etc.
AHR can wait since you don't know if or when you're going to have one. That also depends on where you're having it (backyard is different from formal venue) and when they need to know by. I wouldn't stress about that - concentrate on the wedding first!
Just think about what type of AHR you can afford and want to have if you do have one. Once you have decided that, then you can narrow it down to venues, meet with them to see when they need to have the #'s, and work backwards from there in terms of when to send them out and rsvp deadline.