Howdy! Here's a description of each of the campgrounds:
https://bluegrass.com/telluride/plan-your-journey/campingIn short, you have a few options:
*Town Park has very limited vehicle passes and are typically unofficially reserved for those with mobility/health issues or with young children. They're also extremely coveted and you're quite unlikely to get one.
*Lawson limited vehicle passes (intended for RVs specifically) but they're expensive and can also be a challenge to acquire.
*Ilium is probably your best bet because it's only $70 and far easier to get than Lawson.
Here's an older post about Lawson vs Ilium:
https://www.festivarian.com/index.php?topic=32510.0And some somewhat related info on RV parking at Lawson:
https://www.festivarian.com/index.php?topic=37722.0Hope that helps!