If it's not ridiculously big, left side cross draw works well on a GI pistol belt. It works even better if the belt's connected to a LBV or suspenders, especially if you're going to be hanging a crapload of other stuff on there as well.
An added bonus is that if it's in the 20-30 ounce weight range (as most of my favorites happen to be) it balances out the weight of a pistol on the right side very nicely.
Make sure that it's positioned properly on the belt and that there are keepers on either side of it to keep it from sliding around. If it's under 18" or so in length and it's in the right place, you ought to be able to take a high knee without getting jabbed by the chape. (If it's positioned really well, a low knee should also be possible as the scabbard's shape will tend to sweep it out of the way of your leg.)
I've never found it necessary to secure the tip of the scabbard to my leg and I've spent some time crawling around through the woods, getting into and out of vehicles, and occasionally running and climbing. If it's a concern, it should not be hard to rig something up. Consider removing or at least dulling the chape just in case.
Play around with it a bit. What works for me may not work for you.