I think you'll be happy with an auto especially if you got knee problems and having to deal with the daily traffic crawl..

I have two off roading worlds, my own in my 2000 auto, V6 4Runner doing mild off roading and cross country treks... and with a '67 Bronco that I helped a friend build up.. We do serious rock crawling in the Bronco and have broke more parts than I care to think about, in some part attributable to the manual tranny...

The problem with the manual is finesse either in roll backs when you didn't quite make it up a boulder or when teetering on a boulder and one little wheel spin will slip the vehicle sideways, or ever which a way, and put it down high centered on the frame or frequently the driveshaft on the edge of a boulder..

Perhaps if we had the equivalent of a dual transfer case for really low gearing this wouldn't happen, but I seen too many times an automatic come behind us and really finesse it due to never breaking the wheels loose and staying exactly on a perfect track through the obstacle..

I regularly do two foot driving with the auto even in the mild stuff, one on the accelerator and one on the brake using them simultaneously for really precise control and like it..