New track in Ohio

We are thinking about putting in a track in Lebanon Ohio, just north of Cincinnati. It will be on 16 acres, not very big but it's something to get out on.

My biggest question is should I make the track for just bikes, or should I include quads too? I really have nothing against quads, I just like bikes better and so does everybody else i know, but the Kaw shop local here told me there are alot of quads out there. Is it good to mix the two?

Any input would be appreciated, either good or bad. I want to make as few mistakes as possable.

Thanks

Thanks guys
The thought of having two tracks is a good one, the property is layed out in two almost equal sections with a creek between them. The problem is that one side is only accessable from the creek, meaning you have to cross the creek to get to the other half.
So, would I make that side for bikes or quads?

Something else, the first side is all woods, the across the creek side is all open except for a small pond off to one side (perfect for bikes). Would bike riders be willing to cross the creek? It's not very deep, normal pool is about a foot or less, but there is about a six foot bank on both sides that is about straight up. I don't know for sure yet if I can alter the bank without making the army corp of engineers mad. But I'm sure there is some place to cross without dealing with the steep bank, just may have to ride down the creek alittle.