Sounds like you're on the right track. Any idea what type of grasses is in the field? And about what height? I suspect fescue, orchardgrass, bluegrass. It's getting a little late to get a good kill on some grasses, but some of the cool season grasses like mentioned above can still be killed in spite of the first frost tonight. This week is supposed to be warm and anytime this week would work. Also if the grass is 8 to 12 inches or so, no cutting would necessary and actually be about ideal for a roundup application. Killing the grass now and letting the roots rot up over the winter would make things a lot easier come next spring. There most likely will be new seedlings sprout next spring, but tillage should diminish those to a degree.
Applying lime now would also be good, but it's now hunting season and not enough time for that maybe. If you do decide to apply lime next spring, it would be best to do that first and then disk/plow it in good.
I get some of my chemicals and seeds from Southern States co-op and I think there is a store in Manasses. If you haven't already bought the roundup pro, you might want to check with them about a cheaper form of glyphosate called Gly4 it's a 41% formula and works just as good.
And I know what ya mean about rocky ground. I'm very reluctant to plow up a field on account of it. Some areas are so bad I just kill with chemicals and reseed clover and other perrenials directly into the dead grass/weeds with fairly good results.
Last week, I found a interesting "rock" while checking a plot after a good rain. This was a plot that I tilled in lime and a treasure surfaced along with many other rocks.
There's hundreds if not thousands of these through out this area.