Accomodations Will Vary - Be Choosy.
I never carry a lock. I hate carrying gear and packs. So... I simply won't shop or stop unless they let me bring my bike INSIDE. I want it with me. Arms length. Very comforting.
Lock or not I want my bike with me and in sight at all times. I don't want to park it on a rack so someone can scratch it up because it "adds character." I won't enjoy my experience at their establishment if I'm worrying over my ride.
I explain this while thanking the host or owner.
Most convenience store clerks are cool if I'm polite.
Cafe, diner or restaraunt - it's easier than you think - places that offer seating outside are typically more amenable. Many brew houses are cool if they aren't crowded.
I like to eat at 10 a.m. and 3 p.m. on long rides - non-traditional eating hours. Who needs a crowd anyway - so plan accordingly.