I need to drive the Jeep, so I can't guide the plow. *I can only tow
the plow with a strap or chain so it will need to be made to follow
without guidance(other than the direction of pull).

Would a spike harrow work? You could probably change out the number
and depth of the teeth as needed to get it to work right with your
soil. Either find an old one, or make one--there's a ton of pics
online. If you use a clamp system for the spikes to the crossbars you
could add/remove/reset the depth, but even just something simply
welded might be enough. I suspect the fancy adjustable angle type is
overkill for your use. You'd just have to keep an eye on it and pick
the rocks out every so often.

Would a disk harrow cut up the sod enough for you to then work with
your drag? You might set the angle so the disks are nearly straight
on, more as a set of coulters to slice stuff up rather than at a steep
angle as a clod breaking tool. Some of the disks have cutouts which
keep them from getting damaged too badle when dealing with rocks.

You talk about towing from a tow-hook, so I'm guessin you don't have a
trailer hitch. You might look for a twisted clevis that would allow
you to go from a vertical pin type (typical on the older tractor-drawn
stuff) and then drop the loop over your tow hook (see ebay item
250263839746 for what they look like). Either that or bolt/weld a 1/2
thick metal bar on somewhere that juts out with about a 3/4" hole
through it. A lot of older tractors didn't have much more than that.
Or if you do have something like a Class 1 hitch, remove the hitch
ball and use that.

There may be a bunch of older stuff out there that will work for you,
assuming it hasn't all been cut up for scrap yet. In fact I could
have sold/given you some a month ago, but we're cleaning up to sell,
so my brother got out the torch...

--Glenn Lyford