I had the Woods 7500 attachment. It's a 1000x better than a shovel and it will dig up the rocks, stumps and whatever else you want but it's slow going. From the sounds of what your wanting to do and the $$$$ your going to spend, you'll "probably" be very disappointed trying to move those rocks around. Like some of the other guys have said, get yourself a dedicated TLB and don't look back. I sold the attachment and picked up a Ford 4400 TLB 2250hrs for $6k. It needed about $600 and some wrenching to get it right but you can't even compare it to a BH attachment. It snaps trees in half and pulls the stump out in one shot.
This is the ABSOLUTE BEST piece of advice anyone has put forth here!
26 years ago I was looking for a tractor with a backhoe attachment, something not too massive, so I could go through the woods.
Stopped in at the local Ford tractor dealer, and discussed my WANTS with the owner.
He told me: "Don't waste your money on one of those attachment thingys. Give me some time, and I will find you a real machine.
It took 22 months, but he came up with a used 46HP gas Ford 3400TLB with a quick disconnect 10' reach Ford branded hoe ($10,000 total)
The machine had come from a cemetery, was 20 years old, and had 1350 hours.
That machine now has 1900 hrs., is on it's 46th year, and is going to get a manual thumb, and a second repaint this year.
I have it ONLY for my own use. On my small property of 12 acres, it has paid for itself, and rather than renting a hoe when needing one, mine is always available when I need it.
THE MACHINE IS STRONG AS AN OX !!
It has done stump removal (big ones), major yard grading/landscaping, 2 complete septic systems, 1000 gal. underground oil tank, water/electric line, tree transplanting, etc. etc.
The machine has a 2' wide hoe bucket, and a 5/8 yd. loader bucket, and I have set of bucket curl forks also.
Buying that machine was the best equipment choice I ever made.
In the current very good condition, I believe the value might still be $8,000.
For other uses I also have a freshly restored (she's a beauty) 28 year old Ford 1920 ( 2 bottom plow, 60" tiller, and 60" bush hog ).
The moral of the story as I see it is.......
If you want a backhoe: Buy a REAL TLB, that will do REAL work! (don't buy a junker though)
Unless you are going into business, YOU DO NOT NEED TO BUY A NEW TLB!
I am 75 years old, and I will NEVER SELL MY TLB !!!!
I would ask that it be used to dig my grave, but I doubt that a national cemetery will allow that.