Gear wrenches, aka ratcheting box end wrenches. The shorty version will be a good thing. You won't have enough room to get a socket over the nuts, and a couple of the nuts will be only a 1 tooth swing on the gear wrench.
Otherwise, block the XJ, pull the driveshafts, pop the shifter link out, disconnect the 4wd indicator and breather hose. You may find it beneficial to let the cross member drop to get extra room for the top 2 fasteners, be careful that you don't run your fan into the radiator.