Thanks, this is basically what I'm doing.
I contacted Yellow Cab, which fowarded to West Coast Transportation and it seems like a good option for to/from the airport, albeit at 2x the cost of a normal cab. But it's accessible and seems reliable.
I spoke to the hotel and it wasn't so encouraging. They said they would not pay for an accessible cab but I could take the free trolley, which doesn't seem like the worst option (it's maybe a 3-min walk from hotel and it looks like it goes just as close to the terminal), though we have to lug all our luggage on it. They made it sound like we wouldn't be the first people to take all our bags to the cruise terminal on the trolley and if it's the worst-case scenario, it's not so bad; look like 15 minutes, door to door.
But, as I still have a few months until the cruise, I'm deciding how far I want to go in advising the hotel of their ADA obligations and seeing if they'll find a way to do the right thing, as a matter of principle. It's part of the Hilton chain and it really feels like they should know this stuff by now.