At this point I'd go to the one that is closer. For a phone for 288 try
281-546-3838.
Been now at twin lakes. The bottom is very much like Mammoth Lake but with thermocline. Twin lakes advertises 50' depth but so far did not see it. One feature that is awesome and only twin lakes has over others is showers. You can hose yourself while gearing up to prevent a heat stroke (so cool!). You can also wash your mask, wet the BCD, and clean your gear afterwards. However, twin lakes has a major power line going through and nearby a loud freight train kill the look and feel of being outside. There is also a bunch of RVs around the lake, I wonder why would anyone choose to park so close to an active rail road... Portable restrooms.
Mammoth is great because of its size and all the toys on the bottom. You will need quite a few trips to see it all. Absence of a thermocline is a great thing. But for me it is quite a drive, otherwise it was fun. Having an eatery next door is a big plus. From all the places this one looks more like a proper business, not just a weekend dive place. However, the lake has a bit of a smell to it that stays on your gear.
288 is best if you like a "natural look". The weeds, fish, portable restrooms, fire-ants...
But it is small and gets boring quickly, especially with low visibility. Plus, 288 charges for entrance and air a bit too much (in comparison to other places vs its own size). They do have nitrox 32 but they pre-mix it and store in a big tank, availability is spotty. Any gear that has fallen into 288 will probably will not be found.
I am diving my first summer, I have no idea what is up with visibility. Is it a seasonal thing or out of ordinary? As far as I can tell, if you dive near the shore line anywhere, the visibility is better. Closer to the middle of the lake and it becomes even worse.
I am thinking of going next Saturday to a blue lagoon in Huntsville just to try out all the local places. Need a buddy.