I've read a lot on the subject, and the ranges vary between writers by a good bit. I got fed up with reading so much, and decided to start figuring out things for my self about bobcats.
From my personal experience, and talking to trappers(a very good information source!), I've found that the male cats will generally range over a wider area than the females. The extent they travel will vary depending mostly on food, and terrain. If there's plenty of prey, and cover the range may be as small as 1 square mile even for a big mature male. With plenty of prey, and good cover, a female may range in an even smaller area.
From what I've learned, bobcats can stick pretty tight to as little as 1/2 square mile, or range over several square miles. A female with small kittens will generally stay within a small area untill the kittens can hunt for there selves.
The biggest thing in a hunters favor(here in SW Virginia anyway), is that just like house cats, bobcats tend to travel defined routes during their prowling. Even if the cat is ranging over a very large area, it'll eventually end up right back where you either saw it, or found it's tracks.
Good luck on hunting your cat! I've been after them pretty hard for the past several years, and it's proven to be the hardest animal I've ever tried to hunt. Nothing else even comes close to comparing to the thrill I get from hunting bobcats. Just as soon as our deer season(gun) goes out next week, I'll be wearing the mountains out, squealing like a wounded animal, and watching the bushes for a cat!