Go there, sit on your butt and trim superfluous stuff out so you can see the tree. Take pictures of all sides from 4 or 5 feet away and go home and study them to decide upon a design and plan for getting there. Once you have that go back, trim it to your plan and dig it up. Willows are notorious for being survivors. Use this rule to decide which of two branches to remove: Keep the smaller branch in a fork, remove the bigger branch in a fork. [There may be a wiser choice at the first junction (near your hand) where the bigger fork would give you more believable taper.] This is going to be a very tall tree unless you elect to chop it lower than there are branches now. If you do that kind of chop it will be 10 to 15 years before this becomes something of beauty or interest, the bark being the most interesting feature now and would be mostly removed in a low chop. If you go for the reduction in size at each fork the tree will be tall, but will have taper in the upper section and will be pleasing in 5 years. Don't make the choice just based upon time, choose what you want in the end.