Just West of Loveland is a campground full of long term campers. Riverside or Riverview Campground. We stayed there in July. Nothing fancy BUT it was wide enough spots you could put your slides out which is more than the others we saw.
We live in Colorado and just purchased our first RV. For our first two trips, we stayed close to home until we got things figured out. The park we stayed at was Fort Collins / Lakeside KOA Holiday. There were many long term campers there. It's a really nice park and the people are really friendly. Highly recommend it.
Glad to hear about the Ft Collins KOA. Been told horror stories about the place so we South of Denver to the Colorado Springs/Fountain KOA which is prolly the 2nd best KOA we have stayed at. Renting cabin there Sep 19-23 instead of pulling camper.