Head up to Leadvegas man... cheapest place around (by a big margin usually) for 100. You drive right to the pump & fill up. Gravy.
VVJC will tell you to F off unless you know someone there, they're not big fans of sledders obviously! If you get to know some folks over there though, they can get it... but that's a pain, and I'd assume they're pricey still too.
Rifle is decent I've been told, but way further than the Ville from you I'd assume. Next closest is grand county, Kremmtukky isn't far if you take Trough road, but they've got us on their radar, and are JACKING us for fuel up there.
Never tried glenwood... might call them. They're not listed on 100ll.com, but Leadville is $5.25, and Kremmling is listed at $5.90... but I've been there numerous times where price was higher than listed, I'm thinking they jack prices for sledders in the winter. Granby is listed at $5.40 right now... that's usually accurate from what I've seen, I fill there often.
Nobody up here carries race that I know of, so most of us run 100...