I would like to do as you have done, jehb2. should I first ask to see the contract, or have him put all of this in the contract?
If you're dealing with a scammer (your apparent concern), I'm not sure what a contract will do for you. So Mickey Mouse signs his contract with his Mickey Mouse signature. Now what?
No. Your only concern is "does he have what he says he has"?
Step 1. Ask to see some written confirmation of the reservation. He should scan and send to you. That will confirm dates, unit size, unit # (if already assigned although sometimes specific units are assigned upon check-in). If the unit number has been assigned, call the resort and ask where the unit is, what the view is, etc.
Couldn't you just call the resort and have them confirm that the alleged reservation holder has the alleged reservation. Probably not because you'll most likely be told "we can't give that information out to some stranger who happens to call in". They don't know you, have no relationship whatsoever with you.
Step 2. Payment. Assuming you're going through redweek and your particular arrangement is that you have to pay the owner upfront (rather than pay redweek who will hold your payment in escrow until after you check in), then pay using a method where you have some recourse in the event of fraud. I'm talking about a payment methodology like Venmo where you pay whatever amount and tag your purchase with "purchase protection" (you have to affirmatively select that tag or you won't have the protection). In that way, the "seller" is notified you have purchase protection and you (and he) can be sure Venmo will go after them if Venmo is forced to pay out a claim.
The purchase protection insurance coverage does cost some modest amount of money, and is actually charged to the seller so that he very clearly sees that you're protected, and the seller may (or may not) want a second payment to compensate him for that cost.
Can you then relax and dream sweet dreams about your certain upcoming vacation? Heck no!
Step 3. He should immediately then replace his name with your name on the reservation. And then you should call the resort to confirm you're on the reservation. If not, you know what to do: call Venmo and exercise that purchase protection!
And step 4. Assuming you're on the reservation, keep calling that front desk periodically to confirm you're still on the reservation.
What you want to do is avoid the scenario, often encountered by resort front desks, where the family that came to check in was nowhere to be found on any reservation. Result: crying kids, parents who lost all their money and were then stranded without anyplace to go.
It's hard to believe that anyone would be that evil, but there are apparently countless such people out there.