I've no direct experience with the 311, though much with the 316. I'm going to guess that performance will be tolerable, but nothing to write home about. It will, of course, depend somewhat on whether you drive around the empty box or, as I did, add everything including the kitchen sink. My five-cylinder had 154 hp and 243 lb/ft, whereas your four would be 108 and 200. It probably augers well that the 311 makes only 70% of the horsepower of the 316, but has 82% of the torque. On flat ground with a light van, the difference would be limited, I think, though in hilly terrain, where you're often downshifting and running well over 3,000 rpm, the diminished horsepower will be a factor.
Originally Posted by Christian P.
I'm unclear whether the weight and frictional losses of the 4x4 system will have much effect. The few US conversions I know about have lost 1-2 mpg but seem to drive about the same. No knowledge about how big a factor a purely factory system is.
Overall, my OM647 did a fantastic job of lugging around 9K pounds; it was more than fast and powerful enough. This suggests to me that the 109 horse 611 will do well enough with a reasonable load. (And should you happen across the 127 hp version, I'm pretty positive that would work for you.)
I'm sure, however, that others will chime in with more direct experience.
2007/2012 custom Jeep Rubicon expedition motorhome
2004 Jeep Grand Cherokee
2006 Honda PS250 Big Ruckus Expedition Scooter
1996/2002 Honda XR600R highly-modded