Define "take them on". Define "them".
Rural small market radio success has always depended on reaching out 5, 10, 15, 20 miles or more. The advertising merchants figure most of the people living in that two square miles will tumble into the local stores with or without advertising costs. The reason they get involved in radio advertising is to reach those people several miles out in the rural area who could, at the end of their driveway, turn one direction to go shopping in Murfreesboro, or turn the other direction and go to a neighboring town to shop.
If you just want to agitate the electrons and send some music to a few people for the personal satisfaction of it, go for it. If you hope to be some kind of advertising sales success story, you may find it tough if "taking them on" means competing with the company that owns the existing AM and FM already there.
At 980 on the AM dial WWDR "walks with LONG legs".
I have conversed with a manager who works for the same company that owns the AM and FM and I suspect you will find they don't leave a lot of loose, unclaimed advertising dollars laying around to be easily grabbed.