North shore, get off the main road at the lighthouse and ride all the way from northshore till Arikok and San Nicolas.
But be carefull the rocks are really pointy and most carrentals don't provide Insurance by damage done by riding northshore or forbid to do it.
Also when you get stuck I am not sure if a towing company is coming to get you.
But other than that its fun to do!!!
North Coast in general is a great place to take your Jeep.
Starting up at the lighthouse and making your way down to the Natural Bridge tourist shop (bridge is no longer there) is an EASY trek for a jeep!!!! You wont come close to needing to activate 4X4 for any of this. I would compare this to an old dirt road with awesome scenery and a decent sized rut every now and then!
Beware of sand dunes (you will encounter a few but they are easy to avoid) and if you see water/puddles on the trail/road (RARE) be overly cautious and stay away!!
Once you get to the Natural Bridge tourist shop, if you want to get a bit more adventurous, off of the entrance to the parking lot is a place to turn onto another trail (a right turn if you are facing/going into the NB tourist shop parking lot). The trail is not marked at all but easy to locate if you are looking for it. If you take this, it is more like a trail and requires you to be more attentive. Even on this trail though the chances of getting stuck are next to nothing.. In fact, just to prove a point we went through it in 2 wheel drive last year....
If you end up trying out this trail, following it out, it will take you to Andicuri Beach. Ill reiterate again AVOID WATER!!!!!!!! I say this because at Andicuri there are some puddles/streams near the beach (very easy to avoid!!!) and while you can make it through them the risk is far greater than the reward! We played here last year, went to turn around and a tire dipped in some deeper sand at the edge of one of the puddles and we got stuck. 5 hours and $300 later a tow truck had pulled us out. Not a fun addition to the trip!! Thank God for the super nice locals that stayed with us until we got out!!
If you continue along the coast past Andicuri you can go for another mile or so I guess before you will be blocked from continuing (at least by my standards) and forced onto a "road"/trail. This road/trail takes you right by Damari ranch and will eventually spit you out on a paved road.
Do it whether on a tour or in the Jeep but as others mentioned your Jeep company may have rules against it!! Weve rented from Royal and they do not say anything forbidding it (that I have seen/heard) but when we went to the NP a few years back we saw some jeeps there that had plaques on the dash that said "No Natural Pool......." It was kind of funny to see because all of these jeeps were AT THE NATURAL POOL!!
We go to the NP every time
First time (in the jeep 2007)... yeah it was hairy!! No clear trails we just kind of made our own path and it was fun but scary.
A few times after (in the jeep) trails have gotten MUCH better and there are even some signs.. It was nowhere near as scary as the first.
Last time (with Aruba Sunrise Tours).. Tess(operator) led us in via an entrance to the Arikok natural park that is more in the middle of the island and the entire path was a pretty clear marked and relatively easy trail.
Here is a Google maps link showing that entrance to the park...
........if you flip over to earth view you can even see that the satellite "sees" the trails. Keep in mind though, while these trails are much better marked and visible than in years past they are still not "roads" and will require careful/slow navigation.
BTW.. Arikok national park (which the Natural Pool is a part of) has a fee... (I believe $10pp/per day)
Navigation... Remember that the Divi Divi trees always point towards the High Rise area of the island! :-) You literally cannot get lost!!