I have driven a 600, but not a 700. I like working on my cars and I just feel uncomfortable with a hybrid. Maybe I’m being silly, but is what it is.
With the amount of tech involved in cars these days, it will not be an easy feat to work on either a 600 or 700, bar from oil and filter changes and light maintenance. I know that there is a version of the 600 in OT form in Australia. See below:
That said, having driven a 600 and the 700, the hybrid powertrain is a million miles ahead and better. Better power, torque, fuel economy (not by much), etc, etc. The only downside is the battery taking up space in the trunk.
Enters the beauty of the 2-row OT. Pretty decent trunk space and not very much affected by the battery.
The 3-row is another story and a said one. Some people make it work, but the shelving system is laughable at best. So, if you need a 3 row to crunch your kid or their friends and are hellbent on an LX with a decent trunk, you only have the 600 as a decent option. But you will lose that outstanding hybrid engine with a ridiculous amount of low-end torque to go off-roading, since you mention you plan to do that. Oh, and since you are off-roading, you also lose the holy grail triple lock feature.
You can "build" a 600 Overtrail by slapping the 18-inch wheels and some decent tires on it, but you lose the two most amazing features of the 700 and you save almost no money.