Backyard track design help

[250Renvy]

I have about 5 acres I have started developing a small track on, but want to expand and make in into something awesome. I found this supercross track design that fits exactly in my space, it's just small.

Can someone interpret it for me and/or duplicate it and make it bigger much bigger. I don't know what all the numbers refer to.
I'm not sure if this is the best place for this so if you have suggestions on what part of the forum it would be better suited for or someone that would know better that would be apprecitated too.

<a href="http://img259.imageshack.us/my.php?image=sxtrack32nx.jpg" target="_blank"><img src="http://img259.imageshack.us/img259/5479/sxtrack32nx.th.jpg" border="0" /></a>

[Robin Hood]

Some of them stand for the height/length/width of things. If you look on the side of some of the jumps they say 7, I guess that would be height. And 30 would be the distance. The bigger numbers like 300-200 etc are the lengths of that segment of the track. Looks like a good track.