Hi Kellie,
I lived in UK for 3 years & returned to US and have been going back and forth for a while.
Answer to your questions:
1)I started to read a lot on the web about things that I needed to do prior to arrival in US; driver license, insurance, housing, etc. I had the great expectations as to coming back home & being close to family, friends, being able to shop at Target (my obsession), having stores open for 7 days, less cost of living, lower taxes but they were realistic within reason. As I knew I had to pay for healthcare insurance, minimum vacation time from work, not being able to travel anytime for fun, being chained to work that expects everyone 60 hrs a week, (even on 40 hr weeks). But as with everything, it is what one makes of it, so it was a good return, but I am the sort of person that can be happy any place.
2)Driving licence renewal, getting health insurance prior to getting a job, establishing credit to buy a car, house anything as not being a resident for 3 years with no history made it challenging. So I suggest you use your US credit cards in UK, and pay monthly.
3)I wish I had someone lay all this out for me from choosing the best moving company, (I had some weird people), to steps to take to obtain a place to live, job, insurance, etc.
4)Being able be close to people I know & care, it was the same in UK though I was blessed to have great friends & neighbors.
5)I read a LOT, I mean anything from US magazines (asked my relatives & friends to sent it, and online), to any type US related news, and asked to belong to groups,organizations in my prospective area of move.
6)It took about 3 months, a month to get the stuff, find a place to live, and unpack.
7)I suggest to check the area you are moving to on the web, regards to rent/mortgage, banks in the area, car insurance, cost of vehicle, health insurance, register with job agencies, network way before with friends/relatives about your needs, and take a vacation even a short one to a place that is not by your new home. It helps a great deal.