I just remember it was across the street from Montgomery Wards and had a giant curved screen. I saw "Close Encounters" there when it first came out.
What was the name of the multiplex theater on Platte Ave. near the Citadel seems like there was a drive-in theater right behind it too.
I recall the Peak and was it the Ute(?) theaters in downtown CS. Cooper 1-2-3, saw "Saturday Night Fever" there, actually had to sneak in with my buddy Jason as we were too young to buy a ticket to a rated R movie. heh.
Link to Cinema 70 pictures:
http://www.cinematour.com/tour/us/1715.html 