Good eye Denny. I noticed that too. The light bulbs are not the only thing that isn't vintage in that photo, but overall whoever staged this has done a pretty good job creating the vintage vibe.
At least the back of the truck is being supported in it's old age. I'd guess this is some place along old Rt 66.
What bulb? That's a coil. It wasn't lighting. It was there for chasing bugs away from photo sessions. That was one of the first electric mosquito coils which started smouldering, once you hit the light switch
Truck campers were very popular back then. A boater could take his boat to the lake while camping nearby.
This is close to what we had in the early '70s, 1969 F350 crew cab camper special with deluxe Kit camper. Had a 390-6V and a 19-gallon gas tank behind the seat. Going uphill, 4 MPG. Going 70 MPH down the freeway, 4 MPG. going downhill with the wind at the back, you guessed it, 4 MPG.