Howdy Amigo!
Suspecting you'll be passing through on I-76 on your way through, I'd recommend stopping for gas at the Western in Brighton on Bridge Street. It is about as cheap as any gas you'll find around these parts, and a fill-up will ensure you pass through Denver territory without having to disarm.
Then again, you can stay on I-76 and pass clean through without ever stopping in Denver anyhow. I-76, unless I am greatly mistaken, doesn't even pass through Denver at all.
Or, if you come in on I-70, you can drop off on Airport Blvd, and hit the Flying J just a block south of the interstate to get fuel in Aurora territory. We're east of Denver, and you can OC there and grab a bite across the street at McD's if you like, or at the Dennys which is at the Flying J anyhow.
If you're coming down I-25 from the north, I haven't much to offer by way of suggestions. Don't know that part of town nearly so well.
Blessings,
M-Taliesin