Skip the gravel drive, save for another time. If the trees are of any value you can hire a logger to come in and pay YOU to harvest the lumber. You can then probably clean the rest yourself or find a landscaping crew.

That may take a chunk out of the cost, but nobody said ponds are cheap. $40K is a lot for a 1ac pond IMHO, should be in the ~20K area unless you are moving soil off-site or a distance that needs a dumptruck. I basing that on my experience of a simple 0.6acre pond being <10K without needing soil moved with a dump.