2wd anything out gunning a 4x4 bronco? was the bronco open diff, in 2wd, and running on 4 cylinders?
a locker will definatly help. it wont outperform a regular 4x4 "actually wheeling" i guess trail riding is subjective....but if you can do a whole trail in 2wd its a road

a locked truck can shine in alot of situations, but it wont go where 4x4 is required. i know i can do most "trails" 2wd locked with like 35 in boggers....at least some aggressive and large tire.
my suggestion is a winch like the one i see in the ads of the front page, then a locked sploder rear and a jeep d30 front..actually a jeep 30 or 44 front....then later a locked sploder rear. just so you can see the real difference. in south east mi you can buy and setup for a d30 as long as it was already 410 for @ 3-500 bux if you stay leaf sprung...with a t case ect you should be able to stay under a grand easy.
lots of options.
elec trac/and e lockers are nice.