happy: All the advice given so far is spot-on. If you've never shot PD's before, plan for the most memorable shooting experience you've had in your lifetime to date. You were wise to use an outfitter/guide for your first time too, as no sense driving around looking for a place to shoot and use up valuable shooting days/vacation time.
What has been given as a round count is also completely accurate; you won't believe all the shooting you'll have, especially in a good PD town. Don't overheat that Swift, save it for the afternoon and the wind that will come up. Plan on using 55gr or heavier bullets in it, and if it's a fast twist Swift, all the better, as the heavier VLD's really shine out there. The 204 has become my rodent caliber of choice, and you'll want the most ammo for that rifle.
Be sure to take sunscreen, a sun shade if you have one (with spikes/anchors for the wind), and good high top boots, I NEVER wear sneakers out there, snakes, cactus spines, and other nasties that are best avoided by wearing a good pair of boots. Also be sure to take a good binocular, rangefinder, shooting bench, all your cleaning gear, wide brim hat and plenty of H2O. If you don't have a bench, take knee and elbow pads if you plan to shoot prone. Even shooting from the hood, top of the cab, or off the truck canopy from the tailgate beats prone.
Take at least 100 rounds MORE for each rifle than you really think you'll need; always good to bring the surplus home, rather than have the little furballs thumbing their noses at you on top of their mound at 250 yards, and you're out of ammo!
to get you in the mood, here's some of my crew last season here in Oregon having their way with Skippy and his pals:
Have a great time, and remember to take your camera! We want pictures when you get back.
Oh, and welcome to the forum too!