My experience is that flood plain hogs are every bit as good (tasty) as pen raised, provided you give them a small diet of supplemental corn. Pen raised hogs are fed a different diet - that is all.
Set up a corn feeder in the woods. They're inexpensive and work great. Set the feeder to broadcast the equivalent of at least one (or better two) hand fulls of corn per "feeding". About the volume of corn per feeding as you can hold in your two hands cupped together (or more). Corn is about $5.00 to $6.50 for 50 pounds. That is cheap feed and it works well. A 55 gallon drum feeder will hold about 6 bags or 300# of corn and depending on your rate of application of feed, can last 8 weeks without the necessity of replenishment. Hang the feeder rather than set it on its own legs. A set feeder may get knocked over by the hogs. A hanging feeder, while more difficult to construct, can't get knocked down.
To get them started at your feeder, cut a large hole in the side of and fill the bottom half of a one-gallon milk jug with dry corn. Fill the the jug to the hole with water. Tie the jug off of the ground about four feet. The fermentation of the corn in the jug will smell like garbage in about 48 hours. The pigs love it. They will try to get into the jug if it is hung too low and you will loose that "beautiful" aroma calling other pigs to your feeder location.
In as little as four weeks, the mesentery (the translucent, skin-like, connecting tissue between internal organs) and the internal fatty tissue will begin to turn from mud gray to corn yellow. There is a definite distinctly better taste to supplemental corn fed hogs. They will return day after day, every day to the feeder, even when it is empty, until you begin to hunt it hard and leave a lot of human scent around. Even then, you might get lucky.
I have NEVER aged nor marinated a flood plain hog and have eaten a whole host of them. I have had them arrive at the feeder already marinated after they had filled their bellies with fermented wild grapes. Those three were VERY GOOD hogs!