Yes, I am increasingly thinking I will need something heavier for most of the work.
There are smaller areas where a compact tractor can't get into and I would use the Grillo and mower for that, but the bulk of the ground I could work over with a compact tractor or skidsteer. My neighbor has a 4WD tractor that I can maybe borrow, and he has a box scraper and ripping teeth that would maybe do the job. If not then I could rent something with a tiller or power harrow and then scrape it to smooth it out if needed. But it is hard to see what needs to be done because the undergrowth is so tall and thick - there are foxglove plants taller than I am (I am 6'6") and grass above my waist.
I don't need to get everything done this year, but I do want to get the road frontage done so I can plant some trees/shrubs/etc. for a privacy barrier (the thinning and the brush removal made the house and especially the shop more exposed than I like, even though the road is a private road with little traffic), and I want to do more intensive planting and of the two corners where my driveway intersects with the road.
Beyond that, I want to at least restore and level several paths through the woods so they can be walked without tripping on holes or ruts/etc.
Once I get the undergrowth knocked down it will be easier to keep it down with the flail mower. It really grew up this year because more sun got into the woods and there was less competition from the brush. Most of it is greenery, like grass, ferns, salal (pre-existing and I hope it comes back after I mow it) and this year a lot of foxglove. I've made progress, but there is still a lot of work to do to get it to where it looks like I want it to.