MELGAR,
Thank you so much for your offer of help. I appreciate it! I'm not sure how soon I'll start work on the diner once the kit arrives as I am *supposed* to be spending my weekends on my thesis, not trains! 
Ha!
The prototype for the Whistlestop Diner seems to be Judy's Diner on 906 Eastern Avenue, Malden, MA. It was built by the Worcester Lunch Car Company in 1932. I have a small print that shows Judy's Diner when it had the two roof vents that the model includes, but the print is framed and probably won't photograph well. After several name changes and some exterior ones, too, the diner is now known as The Lunch Box. It is located perpendicular to the street (good for small layouts) and only seems to have one entrance, on the left. The "etched" panels on the model's walls seem to mimic what were probably the original enamel panels.
Amazingly, the diner is a mere 0.6 miles from the Lionel dealer, Charles Ro, located on Cross street, which joins Eastern Avenue. You are correct about the railroad tracks. They ran parallel to Eastern Avenue -- in between Charles Ro and the diner. The track is now the East Coast Greenway (or something) -- a paved rail trail that seems to get a lot of use by city folk. The diner and train store would make for a great road trip for those living in or visiting the Boston area.
Here are links that show what the building looks like now, including the interior:
The interior photo shows a nice "quilt-style" stainless steel back splash in the kitchen. I've been saving foil tops from Brewer's Yeast cans that have a similar quilted pattern embossed into them. If I can pull it off technically, this foil might work as a convincing interior detail.
My instinct about the windows missing their stained glass was correct. I also neglected to mention that the roof line of the model is not prototypical. Hopefully it will be easy for a novice like me to cut off the ends. However, I *have* seen a roof line like it in a homemade diner built to look like a trolley (see my post mentioned previously for photos of the Trolley Stop in Lowell, MA).
It may be possible to simulate the stained glass and the upper window sash. Here are photos of another Worcester diner from the 1930s that show what the original windows would have looked like. Sadly, the stained glass has fallen out and wasn't replaced (Shirley, Mass.):
Finally, here's an end photograph from a similar Worcester diner in Lowell, MA that shows what the roof ends should look like. The air conditioner is located where traditionally two vents were inserted. I will see if it's possible to simulate those vents above the side door on the kit. Also, this photograph shows a common feature for barrel roof diners that might make for an awesome electrical project for someone (other than me). Look closely and you can see sockets for five or six or so light bulbs. They follow the ends and curve of the roof line:
Photo showing the amount of roof overhang with the side door and side windows visible:
I hope that this information and these photos are of interest and gives you or other modelers some ideas for your next kits/efforts.
Best,
Tomlinson Run Railroad
P.S. -- I'm not really a "foamer" but good food, architecture, and trains are my favorite hobbies, all nicely rolled into one :-).
