To get out a very max capacity log, I used a dry plywood roadway, shingled toward the chipper, for skidding it. No way I would have been able to drag it on grass, plus I would have gouged the lawn up.
I've been wanting to build an axle/ wheel set up with a little log bunk. The idea being to have a heavier duty axle and wider, stronger tires for the back end of the log, than the AT provides.
If you're crafty, you can lift one end of the log, slip a fulcrum under, then lever it down to get the other end up in the air in order to get an axle under one or possibly both ends.
Small, round log chunks can make under-log rollers, you just have to keep leapfrogging them.