I'd just like to second Foxtooth on the prior service infantry deal. If you manage to get an 18x slot, you should not have to go to OSUT since you are infantry qualified. That being said, make sure your PT and rucking is up to snuff, the current packet (public info) can be found here:
https://www.facebook.com/media/set/?...0893207&type=3
If your recruiter tells you that you have to go back to OSUT, he might not know about the exception, you simply need to push for it. I know a non-infantry prior service reservist Marine who somehow managed to get a week-9 start time in his contract. (He's in the Q right now)
That has the current (bare minimum) standards for rucks and runs, as well as the current packing list, it is more up to date than the march '09 list that will show up if you use Google. You get that packing list when you get to holdover but it's nice to have this to reference back to.
I've been at SWCS holdover for quite a while (failed selection once, 19 days) and have been here all summer. Some of these guys don't bother to workout extra during airborne school and have it a little rough when they get here.
Like TR says, make sure you really want it, I just had one prior service Marine buddy who VWed today rather than go back to selection, I'm headed out again soon.