Although I'm partial to scratch-building structures, there are some commercial kits that just kick me in the pants with authentic realism.
FOS kits are in that category.
Most are way too pricey for me, but a few are more 'affordable', and well worth the cost.
Mud Flap Cafe Carter Supply Co. Yard Office Burdick Freight Dock, (only 1-inch wide!). Crossing Shed
All excellent kits, and very rewarding.
They're not a 'cinch' to build, but instructions are good, and assembly is fairly straight forward. Quality wood, styrene, metal, card, and paper pieces. Decals and/or signage are included.
Lots of nice extras are included as well, e.g., most items shown in the photos (except for figures & vehicles). Windows & doors are mostly Tichy. Paint & weathering is up to you.
The Burdick Dock will fit between parallel tracks. The little Crossing Shed ("Beginner's" kit) is a 2-in-1 affair... two structures for $10 (mine are intended as yard shacks).
A more expensive kit is the Mud Flap Cafe at $82. However, some FOS kits are well over $300 (which is why I became a scratch builder).
I advise that you try to get them from your LHS... direct-order email confirmation and shipping are very slow. Phone orders speed things up, but delivery is a minimum of two weeks.