Tim,
I have 200 acres about 75 miles north of you, bad infestation of pear. My dad "burned" the pear back in the 60's for cattle food during a drought & it came back with a vengeance. What yellowdog & creekbottom are saying is good advice. I went the skid-steer/rock-bucket route and cleaned up a lot of pear quickly, only problem is you get around 25% regrowth. From roots & dropped pads. After a year the piles must be pushed around or sprayed or it will come back there as well. I have a regular bucket on my tractor, it's just no good for pear-they slide underneath the bucket. I did buy a Rachet-Rake attachment to try buy haven't yet. A skid-steer is a lot quicker than a tractor obviously.
Now the spray: I tried Tordon-it came in one gallon containers and is over 100 bucks a gallon. But it makes over a hundred gallons of spray. You need to add a dye marker & a emulsion (soap) agent to make it stick to the pads & see what you've sprayed. Both of these are cheap. It takes about 2 years to work. And you get around a 70-90% kill rate. So you have to go back. Then Remedy hit the market, same company (Dow) and it's cheaper (I paid 165.00 for a 2 1/2 gallon container last fall) and it works A LOT quicker with a better kill rate. Not quick like Round-up but you will start seeing results in a month or so. Total kill in 6-9 months for me, at a 95% kill rate. You will need to wear PPE and a good respirator when spraying, it's wicked stuff. To buy Tordon or Remedy you will need an applicators liscense, available through a one day course-check with your county agent. If you get it around any desirable trees like say spraying pear under a live oak, that tree will die in a month. Just be warned.
Lastly, I think a multi-pronged attack is the best way to go. Scrape some, spray some and stay after it. I just hired a guy to spray some of mine from a 4-wheeler-75.00 bucks an hour & I buy the spray. If you find a better method-PLEASE let me know. Good luck.