As a teenager I hunted groundhogs just north of you in the southern middle tn area. Back in the 60's, it wasn't uncommon to kill a dozen in a day. I don't see near as many now, probably due to coyotes, bobcats etc........as well as fence row to fence row farming......
Groundhogs love beans......I would stop and ask permission and if they're a problem the farmer will probably tell you where to look and what time of day he see's them....
There are still some groundhogs around, and while hunting them, you could always call crows or coyotes.......