Your biggest issue might be popping a bead. As you mentioned...tires this big can take nails, screws, and minor punctures without leaving you stranded. Getting a 40" spare on/off the door was my concern (not really the functioning of the door itself). Its probably a two-man job. It will also require a 60" high-lift, or a large floor jack under the axle to lift the vehicle high enough to change it. You may have to raise the mount so the tire clears the bumper. And you can also forget any rear vision. So, when you add up all these hassles...it seems to make more sense to just go without, (and it saves you 140 lbs and $600, too!).
Just make sure you got a cell phone...a buddy with a floor jack, 40" spare, and strong back standing-by to come to your aid.