The few times I have been out have all been to Mendota.
I have learned a few things:
1) The dollar-and-change resi will get you in quicker than the sweat line. I've never not gotten a resi draw for a day I put in for at Mendota. There are "two" lines in front of the entrance station the day before your hunt, however, the left is really two lines of resi holders. The right side line is the sweat line, in which you are all but guaranteed to get in, just not as quickly as the resi holders. As soon as the first-come-first-served resi line is done with, all the sweat line folks are admitted. Sleep in your vehicle the night before. An alarm clock is optional as you will be woken up by the sounds of everyone's engines firing up an hour before the entrance station opens. That isn't a bad thing because you'll have ample time for a tailgate breakfast. If you are a light sleeper, bring ear plugs... Some drunk knuckle heads always seem to run a generator well into the wee hours of the morning.
2) Mendota is huge. Observe where the birds come from, and where the birds go, the first thing in the morning (duh). The past few times I've gone, and this may be an obvious statement to most, the main action is done within the first two to three hours of the day. I tried scouting this past Wednesday and the skies were clear by 10 am. Where all those birds came from and where they went, well, I have an inkling of an idea. I will find out for sure though with more experience, just like you'd ought to try to do. Also, this WLA is a big one... I'm going back with a bike next time. The roads are dry, clear and mostly empty around noon. You could walk it for days, but you'll cover more ground quicker with wheels.
3) I noticed this week, to my dismay, that the place isn't entirely flooded yet. The pond I've hunted in the past was bone dry. The entrance station has a map of the flooded/dry areas and that is worth snapping a photo of.
4) Speaking of the entrance station, the folks that work there are helpful... To a point. They move an awful lot of folks through the area in a short amount of time. If you have a question or two, they'll help you out. Just don't expect more than three minutes of their attention or they'll usher you along. I'm talking about three minutes of their attention after everyone has been checked in for the morning. Don't be that guy that makes everyone behind you in line wait the first thing in the morning. Good Lord, you'll incite a riot and you'll certainly not get the help you seek from the station attendants.
5) Once you figure a basic game plan out, bring your gear in by sled/cart. Again, the place is huge and the distances from the parking lots to the happy hunting grounds can be long. Work smarter, not harder. I don't carry a lot, but a few decoys in a sled/cart feel a helluva lot better on my shoulders after that first mile than a few decoys on my back... Especially in a pond's slippery, sucking mud.
6) Most of all, a vast majority of folks out there are good folks who will help a fellow out. Show others the same consideration you'd expect from them. Some dirtbags will pick a fight over who has the right to a coveted spot. To Hell with them. I've had good talks with almost everyone I've met out there. Don't hog anyone's time or space, and always be respectful. You'll glean some good nuggets of info from the real sportsmen.
From your first post it seems to me like you have the proper mindset to look, listen, and learn. I'm in nearly the same boat as you, except I've been there a half dozen times now. I wish you the best of luck, my friend. Let me know if there is anything I might help you with.