Hi,
From what I understand the B-LS operated for 12-18 years. Most of the metro Atlanta Spread has distroyed most traces of B-LS. I believe the Hotel Bath is long gone under the urban sprawl. The same goes with the Roswell.
Several places to look for items that found when researching the Gainesville Jefferson & Southern/Gainesville Midland railroad was that Railway Age Gazette (and all the alternate titles it held from about 1860) noted an unknown (to me and most I've talked to) Gainesville & Dalonega narrow gauge. It had about 2 miles built but never was able to afford crossing the Chattahoochee River to get to Lumpkin County. Via the State archives and the Public Service Commission (your state might be the Railroad Commission) annual reports, I found out that the G&D finally become the Gainesville City Transit company owned by Georgia Power.
I also found part of a 1918 era track plan in the Dekalb County Records room showing where the sg Roswell connected to the sg Southern.
If your line ran through relatively large towns, Sanborn Insurance maps are available.
When I researched the GJ&S, I found a web site that had them on line for free. It is now gone and I have not looked for other sites. I found fascinating ng/sg trackwork in both Gainesville and Winder and found dual gauge trackwork in Monroe GA. It showed possible evidence of a Ramsey transfer. 4-rail track in the middle of a 5 track yard. It looks like the patent drawings of the transfer with the 4-rail depressed into the ground and two outside rails on the level ground to support timbers to hold the trucks as the car was rolled over the pit.
The Gainesville and Northwestern was a SG line to Helen for the lumber. It had up to seven route miles of dual gauge for a logging companies 42" Climax and some shays used in logging.
I am interested in the the Caldwell Traction Co but it does not fit the topic here. If you would like, my business board (Glover Locomotive Works) is available. Just go to my web site www.dougsrrshop.com, got to Glover and sign up for the board.
Doug vV