There are many ways to handle your situation. Here is my opinion:

1. Concentrate your work flying on UA and US, crediting everything to UA. (The reason to prefer UA is the much lower fees for changes on award tickets. US's only real advantage is lower redemption levels on the most expensive awards.)

The side effect is you should be able to accumulate enough flying for Silver or Gold status, which would get you the priority security and boarding benefits, Economy Plus, and possible first class upgrades. Note: Except in limited situations, miles from credit card spending will NOT count toward status. It's only actual flying.

2. Get the UA Explorer card, NOT the Club card. You should be able to find an offer for at least 50k miles on signup and first year fee waived. The reasons to take this card are: priority boarding until you achieve status, award ticket upgrades after you achieve status, primary car rental insurance, all in addition to the generous signup bonus. Also, put at least $25k on the card and you'll earn a bonus 10k miles.

The Club card is definite overkill, especially if you have to pay the annual fee. The higher earning on spending isn't really worth it and you're not flying enough to take advantage of the lounge access.

3. Sign up for the Skyguide Executive Privilege Club. There is a thread in the Amex forum here with a $20 first year fee link. That will offer you 12 lounge visits (and 12 gym visits) for only the postage needed to send in the rebate forms.

4. Next time a 100k signup offer comes along, sign up for the British Airways Visa. If you're flying short flights around California, BA miles are an incredible value on non-stop redemptions on AA and AS. For example, a roundtrip LAX-SFO is only 9000 miles on BA. These are especially useful when the points price on WN is high.

5. It sounds like most of your award travel will be inexpensive domestic routes. If so, you may want to think about a 2% cashback card, like the Fidelity Amex. Just make sure, before you dump spending on miles/points cards, that you'll actually get good value from it. (Another option, as mentioned, would be a Chase card that has a large signup bonus in Ultimate Rewards points.)

If you post more detail about how you want to use miles/points - destinations, class of service, etc. - we can give more detailed advice.