Here's what I found this morning.
$23 to $25 per night. That's 2 vehicles and 6 people max. Having never camped there I don't know how strict they are about it.
Campsites by number
I believe this is campsite #20 in the photo.
Fuel and food.
There is a store at the lake within walking distance of the camp sites. The hours are limited and it was closed so I don't know what kind of selection there is. The building looked like a 20' construction job site office trailer.
Greenville to Antelope lake is aprox 33 miles.
There are two gas stations. A full grocery store and places to eat (the hours have changed quite a bit throughout the years).
Quincy is the county seat and is aprox 44 miles away.
There are much more choices and a cycle shop on the main drag.
Janesville is closer (aprox 21 miles). It 95% dirt all the way to highway 395. I haven't taken that route in a few years. Last time I did, there was lots of cattle and slowed down our progress.
Genesse Valley is aprox 16 miles away.
Lat/Long 40N 02.570' 120W 45.287
They have a sandwich shop (maybe more but it's been a while) that is open on the weekends.
Store phone number
Notice I didn't feel like writing anything down
Taylorsville is aprox 23 miles away. They have a small general store, a post office, a salon (in case you need to get your hair done) and a bar. Yes that is all of downtown. Almost captured in this one pic.