Conceptual Stages of building a motorcycle track IRL

[Chest2Tank]

So I have a desire to build a 1.25 to 1.5 mile long track with 30+ turns for my own amusement. I have absolutely no idea how to design anything outside of photoshop and Illustrator, but I'm taking a crack at SketchUp which you can get for free. I know there are CAD proggies and such, but that's way more technical than I want to get at the moment. Anyone have an interest in playing around and giving me input on your designs?

Also, I'll take any input on this thing because I seriously plan on building this in real life starting in September.

Let's keep the facilities out this discussion, let's just talk about making a fun, yet safe track. Think of the dragon with run offs and kitty litter

Let's have some fun!

BTW, I'm not a troll. I'm on about 7 other forums, so checking all of them would be a huge time investment. Being that this forum is pertinent to the information I'm requesting, I'll check this thread regularly.