The parking lot for the Visitors Center at Sandstone Ranch is near Longmont and has great views in all directions. Limiting magnitude there is about 4.9 so it's a bit darker than in Longmont. Ball field lights are occasionally a problem. They are low to the north horizon so usually don't bother that much as we're usually looking to the south or east. Cars coming into the parking lot are more of an issue. A nearby car dealership uses full cut-off lighting so it's not a problem -- kudos to them!!
From Longmont, head east on Ken Pratt Blvd (Highway 119) and pass the ball fields on your right. Turn right (south) on Sandstone Drive which is just after the ball fields and before the Hajek Chevrolet auto dealership. Follow the signs to the Sandstone Ranch Visitors center parking lot (0.5 mile).
(You can move and resize the map below.)