The "Old West" is such a broad archetype--on a level with the medieval "knight in shining armor", or the Japanese Samurai. In the process of making an "Old West" layout, though, it seems like a little more specificity is needed--even though everyone knows what a cowboy looks like, decisions about terrain and scenery need to be made.
The geographic area of the "Old West" covers more than half of the continental United States, and includes forests, plains, mountains, deserts, canyons, plateaus, coastal lands, unpopulated areas and cities.
Logging, mining, ranching, farming and all sorts of other industries are appropriate for an Old West theme--if one side of your layout is logging, is that not an "Old West" theme as well, if it is a 19th Century Western American logging operation? One assumes your 4x8 doesn't run from Arizona to the woods of Maine.
I may be belaboring the point--but sometimes "Old West" just isn't specific enough for a history freak like myself. Personally, I'm big on West Coast "old west" myself--specifically the great Central Valley of California and the western Sierra Nevada, including fun stuff like the Gold Rush, the Transcontinental Railroad, etcetera.