where to begin?!

The concept of moving across the country is perplexing to me. Where do I begin to pack? We are flying and taking as much as we can in suitcases (thank the Lord for Southwest Airlines and 2 free checked bags each), and the rest of what we want to take we are shipping. We are going to sell all our furniture and our car. The idea is to take as little as possible, only the things that are sentimental/irreplaceable/easy to pack, and going to re-piece together the rest after we move in. But...what am I going to want?! What will be worth it to take and what is easier to just replace?! Ugh. And, how come books have to be so darn heavy and so many different shapes!? I figured out that the large flat rate boxes from the post office are the best deal to ship our books, but for the rest we'll just do the regular slow parcel post. We're still going to save a ton of money over using any type of moving service (I've looked into them all), but sheesh. Moving is no easy task, and moving 3,000 miles away is daunting. Thankfully, I am not too afraid to get rid of things, because after all, most of it is just stuff. I would like to think I'm not too attached to just stuff. We are moving to be closer to family and reduce our cost of living, so that is what is important. We will have a few months to piece back together furniture and things we'll need for a new apartment, since we'll be living with Derek's parents in their massive, beautiful new home for a few months while we're getting on our feet.
On a side note, I am thankful we'll be moving to a place with friendly faces and where there are people that we love. That is one thing that is definitely making this transition exciting. Really, it is one of the main reasons we are going.