do not have actual plans but have many suggestions: I would build the frame out of good strong angle iron, then install a phnematic wheel on each side of the swinging gate for the weight to fall on. Then screw a pt 2x4 to the angle iron for the slats to screw to. Install your hardware and locking mech and you should be set. The pne. tires will roll nicely on dirt, grass or better still a poured concrete drive.
If your not a qualified and experinced diy, then I would consider having this all pro built, especially since there will be many welds.