Were you able to drive / sit comfortably in a car with this setup--i.e., the IWB down the pantsleg?
Remember, my 629 has a 4" barrel. Between that and the fact that the Hoffner's holster holds the gun quite high (cylinder sits on top of my belt), my 1911 holsters ride a lot farther down my pant leg than does the revolver. So, no, I've had no trouble at all driving or doing anything else. The CABO holsters appear to sit a little lower, but not much. And, the OP is asking about concealing a gun with a 2" longer barrel. That will make some difference. How much, I can't say. I would be willing to try it, myself, even though a 6" revolver is larger than I'd
prefer for concealed carry.
How about access time? It seems to me that such a setup would be so slow as to almost negate the possibility of a critical response.
I used the Hoffner's IWB as my primary IDPA competition holster for that gun for about 6 months! Not exactly
slow. A strong-side IWB holster is a pretty quick draw (compared to cross-draw, shoulder holsters, SOB, etc.) and the fact that it's a revolver not an auto doesn't affect that much. Again, a 6" barrel will be a little bit more unwieldy, but I don't think that would be much of a concern.
That implied problem--critical response time--is the reason I haven't really considered concealed carry for such a firearm.
Is drawing an IWB-carried revolver slower than drawing an auto carried the same way? Maybe, but not by more than a fraction of a second. The bigger issue is that revolvers are not flat-sided and slim like most autos. Finding a comfortable set-up is very important. And, you'll just have to try it before you'll know if it works for you.
Is this the way to go for the forthcoming National Parks carry?
It's what I often carry hiking in our State Parks here. Comforting to have decent .44 Mags on hand just in case.
-Sam