The nastier the day, the better. Cold, wet, misting rain = perfect goose hunting day.
You are going to spend your time in rice patties, muddy fields, huddled close to the ground peeking out of a blind, and basically feeling like a muskrat.
A good pump 12 gauge with #2 through T shot (some folks use BB or BBB, but I've never found a need for that large a shot). Make sure the gun is solid and can handle a less than stellar environment.
As far as outfitters, I really couldn't tell you. I've always done my hunting on leases or public land, with the occasional invite in the Eagle Lake area (but that was years ago and I'd be lying if I told you I could remember the name of the outfitter). And I've never hunted up in your neck of the woods.
Having said all of that, it's a lot of fun. Geese are hardy birds with great eyesight. They can be hard to get, especially later in the season. They are an aquired taste though, which is one reason I got out of really hunting them years ago - never liked the idea of killing birds and not really putting the kill to good use. (I have since, however, been introduced to a goose summer sausage that is nails and am contemplating getting back into the sport).