The best media to use would be fiber, in fact, if you want any real bandwidth, I believe fiber will be about your only choice.
You could use multimode without any trouble, and the electronics are much cheaper. So you need two strands of multimode fiber between the two spots, then a media converter on each end that converts the fiber optic signal to 10 or 100 mbs ethernet.
That's all there is to it, you can find quite inexpensive used stuff on ebay, or if you want to look at the high end of prices Black Box has a pretty good web site that can help you select what you need. Do keep in mind that multimode fiber for this will be terminated in either an ST or SC connector (generally) and you need to get converters with fittings to match.
Good Luck! It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com