Dave--You already have enough for the flights, but you had better move quickly. In order to do so, you should check with American as soon as possible and see if you can get the two seats to Hawaii. Then, you can dump 16K of your AMEX into US, giving you 57K US. US and AA are still combinable for awards, so you will have a total of 70,000, enough to get you your two tickets to Hawaii, at 35,000 each. Only problem is you may have to dump the 16K into US before you know if you can use them, and you can't reverse it, from what I understand.
Another way with your miles is to take separate tickets on US and United, but I'm guessing that your wife-to-be won't like that!
As to the hotel ideas, the suggestion above is a good one.
Djlawman