After all the discussion, I am leaning toward renting a ground-level brush-cutter and then using my troy build tiller after. But I love the idea of someome else hauling all the blackberry canes away.

So my preference would be for someone to cut all the undergrowth down and remove it, then I use my tiller to rip out all the roots and rake them off (I can handle that).

THEN plant the 2 dogwoods and 3 sourwood trees I received this week to re-establish shade on the ground but not high enough to shade my veggie garden.

The slightly better alternative is someone with a mini dozer or bobcat to scrape the ground to get the blackberry roots and ivy out. I had a 50'x6' ridge removed last year and that worked great.

I appreciate all the advice. It is adding in my mind to the best solution for me.