A lot of good points made in this thread. I've owned one vehicle with a locker (1st gen Tacoma) and one without, my 3rd gen sport. I personally would take a clean, well kept vehicle that doesn't have a locker over one with a locker that needs TLC. As mentioned, you can always add one if you end up finding the need.
Assess your needs and your intentions with the vehicle. If you've never needed one and plan to run similar roads, you may never need one. But on the other hand, if you're wanting to do a little extra exploring and have that extra piece of mind, it's a great feature to have. I found myself using my locker when I was feeling a little extra adventurous, and will admit that it was necessary to get up or out of some steep, rocky, or slippery areas that I normally would've been stuck. When I bought my 3rd gen though, I was okay with it not having the locker, mainly due to how clean and well kept the vehicle was- again, you can always add one.
Good luck. Oh, and if you have a friend or nearby T4R member in your area with a locked 4runner or Tacoma, it wouldn't hurt to see if they'd be willing to take you out so that you can compare the see the potential.