Just keep in mind that the thing that is hard on it (while in 4WD) is turning when there is too much traction...

So if you have to take a tight turn and you've hit a dry spot, slow way down to reduce the amount of force that the drivetrain has to deal with... or better yet, take it out of 4WD.

One thing that I learned here is that, once the hubs are locked (after you've engaged 4WD for the first time and as long as you haven't backed up since then with 4WD off (assuming you were going forward when you engaged 4WD in the first place)), you can switch in and out of 4WD at any speed.

It's just that initial one where you have to be going less than 25mph.