I have a 2011 not a '12 so not everything may be applicable.
If its set up right its comfortable for a 500 mile day, at least as comfortable as any bike of such design is going to be.
In my case, set up means Rick Mayer seat (stock is awful imo), Rox bar risers, madstad windshield brackets and screen. I also use foam grip covers because I like a fuller grip and a slip on throttle rocker for long highway stretches. You won't mistake it for a Goldwing in wind managment or seat comfort but for what it is, its good.
I also just had the suspension upgraded on mine, haven't had time to really test it but it has to be a good thing as the stock stuff is so wimpy.
Mine has been getting around 55 mpg on extended highway cruising at a steady 65, one one spirited stretch with a lot of 75 and 80 my friend (who has an '05) and I dropped it down to just a bit over 40.
As an aside I did a few gps measured high speed runs with mine with the factory bags on. Essentially the bike is done pulling at 105mph, it has plenty of tach left but just not enough power to pull it. Given enough time it might slowly pick up a few more mph but I doubt too many. Not usually a concern but I found it interesting and thought I would share it.
'14 HD FLHR
'01 HD FXD
'09 HD XR1200
'79 BMW R100