We've gone to ND probably 10 times over the past 15 years, almost always free-lancing. The last 2 years though I've had a vendor take me to Mouse River Outfitters in Kramer and they're AWESOME. This same vendor does a hunt every year and it's usually in some fancy lodge where it's more about the chef and lodge than the actual hunting. Once I got invited along I did some homework and asked them to try this outfitter for a year, and they've never gone back to their other outfitters.
The things I like about them, and the things you need to watch out for from other outfitters are:
1. They don't own a ton of land but basically have the whole county locked up through either day leases, helping to bale hay and shovel manure for farmers, etc. A LOT of the other outfitters own/lease 10,000 acres or whatever which sounds like a lot but that gets hunted out quick and they end up saving fields for the next group, putting you on fields that they just hunted yesterday, etc. Be careful at some of the outfitters and big fancy lodges (esp around Devil's Lake) for that reason. Also, be careful around some of the guys that mostly hunt deer or just farm but call themselves waterfowl outfitters. We ran into a bunch of them when we were free-lancing and most didn't have a clue what they were doing. Plus we ran into a bunch of their clients over the years at the bar or gas station, and they were all ticked off because the outfitter would stick them in some ditch somewhere and they'd be lucky to shoot a couple geese. There's an outfitter near Garrison that ALWAYS has hunters in the same field we drive past, year after year.
2. They have 4-5 guys constantly scouting to find the next field. If you get a chance, ride a long with them when they're scouting. It's a blast, and what free-lancing is all about.
3. They're really good guys. You'll laugh your butt off as long as you're there and have a great time.
Their lodge isn't anything fancy, but is really nice, clean, etc. The food is good and the beer is cold. Also, it's on the edge of the typical ND town, so you really get a "feel" for the ND life.
All that said, you could also freelance if you want. There are still areas in ND where you can knock on doors and get permission. It's gotten tougher over the past 5 years though as the last couple years there were 5 trucks circling most good fields and several pickups in the farmer's driveway asking permission. Also, if you're flying in vs. driving, it makes it way tougher to free-lance, especially for field hunting due to the huge decoy spreads needed.
PM me or give me a call if you want any more info.