Well, I have spent more than a few years hunting Arkansas and in fact rarely even hunt Mississippi.... I think I did a rundown on Arkansas guides in another thread, I'll see if I can link that for you shortly....
As far as going cowboy on public land...good luck, it is truly a rough world out there at times....
First and foremost, most places are overflowing with people...I have honestly been in fistfights over duckholes on public land, that is the exception though...not trying to scare you, because for the most part it is simply crowded...but every now and then, when the hunting gets really good in the timber the a$$holes show up.... I have had people set up 20-30 yards from us.... fire random shots just to flare the ducks working our holes and many other things that make hunting public land so wonderful....
Bayou Meto a.k.a. "the Metro" due to the crowded conditions, like many public areas many of the locals have staked out "spots" and don't take kindly to others hunting their hole.... I have hunted it a handful of times, and if you're with someone that knows it and has a few good holes it can be good...but I won't go without someone that knows it...it simply isn't worth fighting the crowds....
as far as getting a guide on public land, per the AGFC regulations section 25.07:
GUIDING PROHIBITED ON ALL COMMISSIONED-OWNED OR 10-00/08-06 CONTROLLED WMAs, WDAs and WRAs.It shall be unlawful to guide waterfowl hunters on any Commission-owned or controlled wildlife management area, wildlife demonstration area or waterfowl rest area.It shall also be unlawful for waterfowl hunters to hunt while being guided on any Commission-owned or controlled wildlife management area, wildlife demonstration area or waterfowl rest area.
PENALTY:$500.00 to $1,000.00
you can see it here
http://www.agfc.com/rules-regulations/code-of-regulations/code_sec25.aspx
now all that being said, I believe your best bet would be to get a guide....but if you want to try the public land feel free to give it a shot, but realize that it is going to take a lot of hard work and time spent figuring out the area (here is a hint, hunt the woods when the water is rising on the rivers, and it helps if the fields are locked up frozen).... and plan on bringing a boat to try and help get a little seperation from the crowds.... personally, I would avoid the Metro as a starting point.... but that is your choice...it is pretty much as far south in the state as you find large concentrations of mallards this decade...but as said before the intensity of their presence is related to the flooding in the area....