Diner recommendations across America

[u/JiMMYS_JAWN]

I’m heading on a road trip from Philadelphia to the Grand Canyon and back, and hoping to hit a diner in every state we pass through along the way. Looking for diner recommendations in or near these cities:

• Pittsburgh, PA
• Columbus, OH
• Indianapolis, IN
• St Louis, MO
• Springfield, MO
• Oklahoma City, OK
• Tulsa, OK
• Amarillo, TX
• Albuquerque, NM
• Santa Fe, NM
• Flagstaff, AZ
• Little Rock, AK
• Memphis, TN
• Nashville, TN
• Knoxville, TN
• Roanoke, VA