There is a thread here that you could find if search were working that discusses at length the public transportation options available. If you really only have carry on, and would like an adventure there are several good options available. In fact, several of them are the "best way"

Just keep in mind that there are no one-seat rides to/from the city from either airport, so your butts will be in a minimum of 4 seats for the journey and the various options will cost between $10 and $21 each, so you should keep that in mind when comparing to a taxi/car.

(Also, I haven't done it so I'm not positive, but as far as a taxi, I think it will run you a lot more than $60....)