Congrats on your new purchase!! You'll definitely enjoy and get a lot of use out of it. Regarding the dilemma: I have a 5 foot box blade that I used behind my older JD750 compact tractor. When looking for a land Plane and the high prices they get for them I decided to borrow a few parts off the box blade I already had. the three point hitch was bolted on, as were the two blades on the box blade. So all I had to do was build an appropriate frame from some steel that I had and swap the pieces over to it. Here's some pics:
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I still need to sand blast and paint to match the B2650. It sure doesn't take much power to pull them. But they don't move a lot of gravel......more for leveling and maintaining. If needed I can remount the hitch and blades on the box blade to move and shape things.
So if you get a box blade to do your initial build on the driveway, it doesn't take much to borrow some parts of it for a landplane.