The A.I, Doesnt build a coaster. Its just a person that wants you to build them coaster. and rates your coaster. Does that answer your question?
There are many different Ai Units. Currently the game is bugged in ai challenge mode with more then 1 player playing. I will fix it as soon as I can figure out whats casueing it.
I wanted to include more things like upside down loops ect but thats very very advanced for most players, so I am sticking to pro players trying to see if they can get it near perfect. where most players will do ok at what the ai unit wants.
Ah okay. You once said you plan on expanding/evolving Roller Coaster into a Roller Coaster Tycoon type of map... which would be really damn cool! Maybe not exactly like Roller Coaster Tycoon as if it were some conversion, but you get my point. Sounds like you're kind of working towards that by starting with missions assigned to the player.
Just remembered that your map is multiplayer... so if this DID turn out to be like Roller Coaster Tycoon, would be cool to see how an online RCT would work out.