you shouldn't have too much issues. Don't be scared to start with a slower motor, especially if its on you already have from your onroad vehicle.
The main thing I noticed when changing from onroad to offroad was that you need to get accustomed to an uneven surface a lot more than touring. IN touring, I found that once I had the tire setup right, it was pretty much the same traction all around the track. In offroad, various sections can be different. Jumps also add another element to things as well.
Offroad is a blast in my opinion, more a challenge but at the same relaxing too. Touring to me just got too intense where it wasn't fun anymore.
If you do running touring, you shouldn't have that much maintenance issues since you are used to more moving parts in the drivetrain.
compared to 2wd mod, 4wd is a lot easier since you got all 4 wheels pulling and it doesn't want to kick the rear out as much if you are gunning it.