Jim,
There is a campground in Fairhope, AL that has a train running thru it. I have never been there; however, it looks like something you might enjoy. If you are ever in the area, it is right off of I-10 in southern Alabama.
The name of the park is Wales West Train & Garden Lovers RV resort. It is rated 4 stars by Woodalls (which means absolutely nothing) . I think that I remember reading that it is 10 or 15 miles off of the interstate.
Check it out