Got under there myself today, actually it didn't look that bad, removing the front axle and possible the rack and I think it would be fairly straight forward.
My leak appears to be possible from the valve gaskets, but not 100% sure, all the bolts on the pan were tight, and a few I could get to on the valve cover were also tight. I hope raising the oil pan with a block of wood to install the TMS didn't cause a leak. It isn't dripping, just surface wet. I guess after 80,000 miles things aren't new either.