I don't find those gas stations shops to be especially "difficult" or even terribly time consuming -- once you know what you're supposed to document. I also go through, take pictures of every "section" of different types of food on the shelves, and close ups of the individual stations, because I cannot remember all that from the list, but then I can go back and so I can refer to it later, in addition to the other pictures. I take (right now) a picture of all the lubes that I can enlarge and say, "Yep, we have this type and this type". When i'm filling out the form, I can say, oh, here's the salty snacks, nuts, jerky, donuts, griller, pizza, fruit, etc. It'll only take me a few seconds to grab the picture, but it would take me a lot longer to do the elimination if I have to read it. In any case, the time is spent at my computer rather than standing and documenting. I also take pics of anywhere I see signage, and usually an extra picture or two of the inside of the store, and then the outside shots, because that way I have back up pictures in case one doesn't turn out. I'm not driving back if I don't have to.
I do like the fact that you get a two gallon reimbursement, and I expand my soft drink collection with the instore purchase, haha.