I remember White Castles in the 50s in Denver. We got our fist McDonald's in Pueblo in the early 60s. I didn't even know what a pizza was until I was maybe 13 or so, we did have a couple of local places that made them, but we didn't eat there.
The link says Dairy Queen was popular in 1949 when I was born. I remember them, but we only went there for nickel cones. My parents grew up during the depression, so when we traveled, we would take bread, some sandwich spread, and some lunchmeat. Later, we might stop for lunch at McDonald's, but my dad refused to pay 10 cents for a slice of cheese, so we ate hamburgers.
Off topic, but I remember traveling to my grandparents' house in Milliken CO (50 miles north of Denver) before the interstate was built. Downtown to Elizabeth St, then North on Hwy 85/87 to Colorado Springs, then all the way across town on Nevada Ave, then back on 85/87 to Denver, where Colorado Blvd was the only way across town. Back on 85/87 to Milliken.