If you have 2k to spend on optics, you can get a MUCH better optic than the vortex. As you already know, for a 1k yd prairie rat you're going to need some pretty stout magnification. I'm thinking start with scope lines that offer 25x magnification as a minimum....
For your budget & needs, I keep coming back to the NightForce NXS 8-32 or 12-42.... just keep in mind, as you go up in magnification, you go down in elevation travel. The 8-32 has ~65moa of adjustment, so the 12-42 is only rated at 45moa which is almost useless IMHO.
Bang for the buck, NightForce is still where it's at. You could find a used USO 5-25 for a little more $$$