i've got a little different twist...
i say it depends on what you think a 'doggin trip is supposed to be about. for me, it is shooting small targets as far away as i can find them (meaning, i don't shoot them if they are only 1 or 2 hundred yards out, no matter how many big fat ones are dancing around at 200 yards). so, my prairie dog rig is built a little different, and is most certainly not something i would ever try to hunt w/ - gun is just too heavy. 22's of any variety, sks, ar-15, ak, or whatever else is not something i'd use.
if you just want to go hose a town down, then any gun you grab will work. as for caliber, for true dual purpose, i don't think a 25-06 can be beat.
for scopes on a dual purpose gun, i would reccomend: vx-3 4.5-14, 6.5-20, or 8.5-25... or, vx-2 4-12, 6-18... it just depends on specifics. if you'll shoot more prairie dogs than deer/coyote hunt, then bigger is nicer. if you'll use it more for bigger game, you'll prefer to go w/ a lighter, smaller scope.
agree w/ smoke on population... besides, you will not be able to eliminate them all unless you use chemicals. and they do re-populate pretty fast.
agree w/ smoke on eating them... probably only one way to get sicker, faster, and that's to handle them w/ your bare hands... i've never touched a prairie dog, and the thought of eating one is pretty repulsive...