We have been cutting trails through an Illinois hardwood forest full of Honeylocust,Multiflora Rose, downed logs and briars for about 20 years.
A chain saw cuts the heavy stuff, after we get in to it through the MF rose with the brush cutter. In 2001, we bought a Billygoat self-propelled brusher. It goes up the steepest hills and pulls me up with it in low gear.
For larger stems, one of the Stihl brush cutters with the buzz saw blades make nice clean cuts without leaving stobs, but do not chop up the thorn bushes like the rotary brushers do.
I have an old Green Machine Forestry cutter with a Stihl buzz saw blade. ZING!! goes the hawthorns.
Below, are my ND fire trail photos. They are used for hiking, hauling firewood, ATV and snowmobile of the neighbor's, access for spraying weeds, etc.
After the trails are cleaned up, use a broad-leaved brush killer in a 4 gallon sprayer or 25 GL towable sprayer to convert the trails from brush to grass.
This works well to get rid of blackberries on the trail, etc.

In the photo, the fence line was later trimmed out and sprayed with brush killer to widen the fire break / hiking trail.
I locate my trails, if at all possible, where I can keep them mowed with a lawn tractor. The slopes that are too steep get 3-4 passes with the Billygoat brusher.
In areas of thorny vegetation, trails are the only way to enjoy a walk through the woods without a suit of armor.
SC