Nope crash, i have no idea how you can work around it.
I had same problem making x-raid. That's also the reason why you'll find there's way to much water in de part before the desert.
You only have 20 cp's, so in order for guys to follow your track you can put models, or make it impossible to find a shortcut by making the terrain undrivable by using or mountains or terrain. The problem with these monster trucks is that they are made for driving on rough terrain, so if you are making mountains they have to be so high and steep the track does not look natural no more. So you only have water as alternative. But that is a problem to. If it's not deep enough people will drive through it, but if it's to deep people will get stuck.
I don't see on how you won't have enough models. There's not so much to see around the ring, besides trees. They could help ya keeping trucks on the track, but i suggest water for doing that, because there are indeed more then 541 trees around the ring
I'm not that big fan of all asphalt roads for mtm2, but if it's your thing go for it. If you stick with it your name will be made, that's for sure. And i can't wait to take on the ring with a monster truck
P.S. you should try and take on knarfke (dunnow if ya know him, he made mtmstarter) when you play gpl. He drives the belgian championship and is incredibly fast there. He just had a race on Silverstone, and asked me to join him in practise. My best lap time was 1.34.??, while he drives a 1.28.??. World record on that track is by a guy named Greger Huttu with a 1.24.??. it's not that much the times they drive, but it's very difficult to control these cars. If you see them driving lap after lap without crashing and at laptimes below 1.30 you just can't believe your eyes.
In 3 weeks time race will be held on the ring, and i know he's practising like mad now to be fast on it.