The first 'Steak n Shake' I ever saw was a drive in. It was built in St. Petersburg, Florida about 1966 and became the St. Pete High hangout. On Friday and Saturday nights they would have at least 3 security guards on duty to direct all the cars driving through the lot.
The first Krystal Hamburger I ever saw was also a drive in. It was in Savannah, Georgia when I was stationed there in 1972. I had never seen a White Castle since I grew up in Florida and Krystal became my favorite and still is to this day.
Not to hijack the thread, but in St. Petersburg we had a store called 'Webb City'. It started in the 20's as a drug store and grew to a 4 story dept store with a 40 seat barber shop and a grocery store and a basement cafeteria, a 7 story furniture city with a big record and music department, a sporting goods and auto center with many gas pumps and a boat city. It took up many city blocks, if all the buildings were combined you could probably put 3 or 4 Walmarts inside. Where the Tropicana Field now sits was the Furniture City and parking lot.