I have a 2001 Concourse while it is not 4WD, it is lifted with several suspension upgrades and mods for off-road travel.
This rig looks really nice, however, it is the Premier model. not the Concourse. The Premier had the square coach windows and lesser upgrades. Not a big deal but point of correction. The V10 is a great engine with tons of power and torque. They marketed these as the sports cars of RV's. The manufacturer went out of business in 2005.
You are right, these are made as duallies. I have heard of being transformed into super single but not a solo single. My rear axle weight wet is 7,500 lbs. I am not sure what those tires/axle are rated for. But thats a heavy rig and with off-road jarring I hope that rear axle/wheels are rated for it. Also, it maybe just the angles, but the rear tires look like they track more narrow than front, this could be issue and I would want confirmed they did not.
I really like the exterior color. He took off the stripes and the gray paint with black accessories is really sharp. I may paint mine one day and this color will be in running. The interior looks very clean, correct and original, except tv and stereo look newer than original. He has a custom front and rear bumper, those are not cheap, and swing out spare tire holder is much more functional than original, the cab entry steps are custom also. The clock does look like it was moved from original area so I wonder if they did any wood work, the wood is solid red oak.
The 4x4 conversion looks new as clean as it is. I know the geometry and overall build will determine if it is successful or not but I have no knowledge of this so I'll leave that to someone else, but I would research the builder if you were interested.
In todays crazy world, this rig IMHO is very fairly priced (I am on east coast and no affiliation with seller). A base rig today will cost in mid 20's minimum, an east coast 4x4 conversion build is $25k at Ujoint, plus those bumpers to buy would be upwards of $2k each. I wonder if he bought rig really cheap because there was undercarriage damage so he did conversion and upgraded bumpers, steps etc....
A stock Chinook off-road creaks and rattles a lot. With the right suspension changes this can be greatly reduced. The chattering from my coach declined significantly after off-road suspension mods.
I would be interested in how this rides, I would like to see better photo's of rear axle as well. It looks like MorRyde suspension removed but couldn't confirm from pics.