We are in south central MO.
The laws here are pretty laid back. Basically we keep a log of our hours... 1000 per year, 600 of those in "core" subjects (math, language arts, science, social studies) and 400 of those 600 take place in the home. We are unschoolers and it is still so easy to keep the kids records, I observe them, record their activities in "educationese" and transfer those observations to a time sheet. It is also a good idea to keep some kind of portfolio- ours is a book list, photo album, and a collection of artwork/projects the kids have completed. (With the exception of the book list these are all things I would save anyway.)
Another great thing in MO is that there is no agency directly responsible for checking your records or keeping track of your hours; we just have it so if anyone asks we are covered. In MO the only people who will ever ask are reps from DFS and even then they must have a complaint they are investigating outside of education- there is no legal definition of educational neglect in MO so that in and of itself is not a legitimate offense. No one
I know has ever
been asked to show their records to anyone
As for groups, I can't speak for other areas (except the city- I know St. Louis has a great homeschooling community as well) but in our small rural area there are three seperate groups, one of which is very large. There are lots of opportunities for classes, fieldtrips, playgroups, etc. Our biggest problem with socialization is picking which activities we really want to do so that we don't run ourselves ragged.
HTH! If you make the move I'd love to know what area you'll be in- we have a fantastic group that would be happy to help you make the adjustment to our state.