I've hunted Pool 1 several times. It is super easy access. You can simply drive trucks down the gravel road on the East side and drop all your gear off near the outflow gate (just before you reach a secondary gravel road that goes out to a substation). Then drive truck back out to the gate and walking back in.
We've hunted right off the levee at the outflow (red X), or sometimes waded out into the corn toward the center and hunted out of standing corn.
Quite honestly, I've never had a great hunt on the Pool, but not because it's a bad pool. Our timing was just bad with lousy warm, windless weather. It wasn't uncommon to flush hundreds of birds that were roosting there overnight, and then they never come back.
Sometimes we have resorted to just sneaking in without gear, waiting for shooting time and jump or pass shooting birds that didn't fly out before legal time. Then we'd set up blinds, decoys, etc.
It's an easy pool to hunt. Simply a matter of whether or not the weather will have birds moving off the refuge. Sometimes it's frustrating because you'll watch ducks flying around on the refuge (to the north) all day, but they'll never come off. Good luck!