Here’s a vintage slide from my collection. I don’t know the location of the diner, but there are some clues in the photo I’m working off of. First is the sign that says “Delaware SPCA”. That places the diner somewhere in Delaware. There is a sign that says “Bay Bridge, Rt 13 – 301”. These two roads, both routes to the bridge, come close to each other near Newark, DE. The photo is 1970s, evidenced by both the cars, and the presence of the reproduction Liberty Bell on the back of the truck. Near the diner, there is a motel, a Shell station and a Gulf station. Anyone remember this stretch of road or have any ideas?
Diner Hunter 
That picture is taken at the intersection approaching the New Castle De Airport. The towers in the back ground are the approach lights for the runway. The diner is gone but to the right of where the trailer is is now the Nissan Dealer. I was just past there the other day.
this is route 13 north in front of the new castle farmers market at hare’s corner
This is actually the South bound lane of U.S. 13 & 40, approaching Hare’s Corner, at New Castle, DE – evidenced by the fact of the “Bay Bridge” sign pointing ahead, which is the way to the Bay Bridge from this point – South. Also, the sign pointing to the right for the Del. SPCA; which used to be West on Rte. 273 (the intersecting road at this intersection). The diner which used to be where the diner in the picture is, was the “Viking Diner” (it closed sometime in the mid-late 1970’s). Now, there is a Burger King at that location. I can’t enlarge this picture enough to see if that is the Viking, in this picture. The Nissan dealer (Mentioned above) is on the Northbound lane, at the SE corner of the intersection. Where this picture was taken, is the SW corner, looking South. These approach lights are gone now – with an improved landing system in place, but the end of the runway (Runway #1) is just to the right of the edge of this picture. (I don’t see the motel that you evidence, although there is a motel on the right, just past that intersection (The “Dutch Inn”).