You should be excited lubbockdave. I've owned a Ruger No. 1 in .257 Roberts for nearly 25 years now. It's accounted for deer and a number of our groundhogs, the farthest away being just over 400 yards - one shot, dropped like a hammer hit him. Mine wears an old 4-12 Bushnell with the trajectory compensating feature in offset rings to get me a bit more eye relief. Much better scopes are available today, but this one does the job for me. Can't help you much with factory ammunition, as I'm a dedicated handloader. For your prairie dogs around there, I'd prefer a smaller caliber and usually use one of the high stepping .22 calibers for that when I come back to your area in the summer (Texas Tech ex - can't get it out of my blood). If you have some leads for me regarding who I might talk to about hunting prairie dogs around Lubbock or further north in the Amarillo area I sure would appreciate it! I've been hunting on a place south of Lubbock for the past few years (a couple of days each summer) but it's getting a bit iffy.
Enjoy your Ruger; they're great rifles.
RonF