Huckie,
I do not know for sure what size tractor you are looking at, but based on your other posts, I am guessing something in the low 30hp range? And based on your description I think your land and mine are not all that different.
That said, I have found the best way to get at the rocks is with my backhoe. But I have to tell you most of the time I am just to lazy to hook it up. I have no problem digging out 600# - 900# rocks with my FEL. Although there would be no way I could do this without the tooth bar and the larger pistons on my Koyker loader. It may take a little longer and make a bit more of a mess but it does get the job done.
Digging around root is a different story. For that the FEL is just too big. So I guess a lot will depend on how many rocks you are planning to move! But if you are going to be doing any serious digging I would NOT recommend a 3ph backhoe. Do yourself a favor and go with a subframe mount. You won't be sorry.
Hope this is of some help,
Gary