the fun fun cave tour in hato mayor is offered by touroperators including transportation, food and drinks, it is a full day tour including caving, horsebackriding aso.
i can absolutely recommend that excursion, i did it myself several times because i know the guys who started that adventure many years back, it's amazing.
just check out the tour reps excursion boards at your resort, the excursion is named Cueva Fun Fun.
an other great organized excursion to leave the resort is the fun buggy tour, you drive your own beach buggy on that full day excursion, around $90.- US per person, driving throu dominican country side and along beaches, absolutely worth the buck.
also found on tourreps excursion sheeds, named Fun Buggy Tour.
have fun
Mike