Narrow Gauge quiz

I was recently reading Hilton’s book American Narrow Gauge and noticed something I had not seen before. Hilton states that the longest ever continuous narrow gauge trip in the US was from Sealy, Texas to Ironton, Ohio. This was a distance of 1581 miles and involved 5 different connecting narrow gauge railroads (Hilton’s book, pp. 110). I was really surprised at this as I would have thought that the longest narrow gauge trip would have been in the west and involve the D&RG. So I set about trying to prove Hilton wrong. I could not do it. The longest trip I could find was one hundred miles too short. So, I pose this question to all of you very well informed NGDF readers; can you find a continuous narrow gauge trip longer than 1581 miles, here in the west? If not, what is the longest one you can document in the west? Details as to route, road and time frame would be needed too. I have what I think is the longest one, but I would like to see some one else give it a try and prove me wrong.
Dick