preparing to move across the Atlantic?

So how does one prepare to move to Europe for 10 months, or possibly 2 years? I have an apartment lined up, waiting for my visa, have all the logistics in order, but I feel like there is so much else that needs to be taken care of. I think I am mostly concerned because of the uncertainty of the next time I will be in the States. I could be gone for as long as 2 years, so I am not just visiting Spain, I am moving! People panic about moving to college, how about moving out of the country! Let's just cross our fingers that I work out all of the logistics before September 16.....