Any guesses on how long that will take, what it will cost, and the odds if it happening at all?

No idea, but it's safe to say that Iran has lost most of their navy and air force already. It's harder to tell how many launchers, missiles, and drones Iran has left however, as it is deliberately hiding and conserving munitions for what they expect will be a protracted conflict.

The other unknown is how far the U.S., Isreal, and potentially other countries are willing to go. Turning the lights off and literally sending Iran back to the stone age wouldn't be so difficult at this stage, but would probably rule out the possibility of a deal that sees Iran disarm and hand over the enriched uranium.