A good driver can go almost everywhere without lockers IMO. When it gets very tough, I have found that having the rear locker is priceless. I have never needed a front locker, but I usually back off before carnage
Your best bet would be an ARB in the rear, or a junkyard swap for an e-locker axle. Be prepared to add some wiring for this although Toyota usually makes one wiring harness with provisions for all options so you should be plug and play, just make sure if you get an axle or third member from a salvage yard that you get the harness and dash switch as well.
