There's some very old routes from TS2004 on the DLS, but they aren't what you'd call historically accurate. About the best one is 'Turks Castle' by trackplate <KUID:129486:1803135>. However be warned that all he did was take the modern West Somerset line's track plan and convert it to Broad Gauge track. The GWR buildings he used were what was available at the time so aren't correct for late 19th century Somerset, but overall what he did wasn't too badly done all things considered.
I've been rebuilding the 'Turk's Castle' route to be historically correct, but it's a long slow project so don't hold your breath waiting for me to upload it.