I've done two transfer-of-points transactions...both times I was getting the points transferred into my account.
The first one was with an internet friend from whom I'd rented a reservation previously. I offered to send the money first; he said no, he trusts me and we went ahead and did the transfer the same day I wrote the check and put it into the mail to him. Of course, my check took 2 days (as I recall) to reach him, and then another 3 (I think) to clear...but I knew the money was "there" and he trusted me, so it all went very very smoothly.
The second time was with a stranger. We called each other (I forget who called who; we swapped phone numbers via email) and chatted a while. Decided we were comfortable with each other. Again, I offered to send the money first (and wait for the check to clear) and while he said that wasn't necessary, I wasn't in a hurry for the points and we had logistical issues (took a few days to find a time when we were both available when MS was open)...so he wound up getting the money from me before I got the points. But the key was we talked to each other enough ahead of time to reach an agreement that was comfortable for both of us. That transaction also went very, very smoothly.
I can't think of a way where one party doesn't have to go first. Once the points are transferred, the transaction is final and once the transferror has the money there's nothing the transferee can do (short of legal action that might or might not work out) to get the money back...
So, I think the key in points transfers, even more than in rentals, is to talk to each other enough to gain some degree of comfort and trust...
Personally, I refuse to do PayPal. Hate them with a purple passion. If a party I want to deal with insists on using PayPal, I won't deal with them. Checks work just fine so long as both parties are willing to deal with the mail and check clearance times...
Good luck!