I doubt that you can restore a Wrangler in 300,000, i would recommend that you start with a FJ 40 Army auction, grab it, fix it up. this would cost you around 250k approx. from there, keep on building it up from there. it comes with a stock 6 cyl 2F engine Petrol. very good 4x4 capabilities, comes with leaf springs, you may add shocks for a better ride.
As for Wrangler, you can grab a CJ7 and have the body work done to match wrangler style, there are people here in RWP who does this for a living. As for power plant, if you prefer Petrol, then 1uz is a good option, with matching transmission from the LC series. if you dig diesel, then i would highly recomend Ikz-TE.
Just a thought to get you started, good luck with your project.