The
Montana Owners Club (MOC) forum is a very active forum. And there are many there who are owners of the 3750RL. Of those many do have a dually, but there are also those with SRW that are also happy with them.
The 3750RL actually has a pin weight several hundred pounds lower than many of the other Montana floor plans.
And keep in mind that there are some here who think you need a dually if you tow a trailer, period. The newer trucks have greatly increased payload ratings over those of even just a few years ago. So check those payload ratings against the pin weights of the trailer(s) you are interested in.