the easy way #1:
charter a plane and fly in
the easy way #2:
arrange a cabby, should be around $200.-US one way, can be arranged with Bronly of IBK Tourist Services on
ibkservicios@gmail.com
the save a buck way:
*** at the main road in front of the Punta Cana Airport grab the public bus, named Guagua Publica, and drive to Higuey.
they run all day long around every 30 minutes, costs around US$3.- per person.
*** in Higuey you let them drop you off at the Parada for Santo Domingo, here they depart 3AMtil 10PM every around 20 minutes, costs US$6.- per person.
in Santo Domingo let them drop you off closest to tyhe station where the Busses for Santiago depart. you need a short cabby ride of around US$6.- for that.
*** i don't know their time shedule, but my wifey is from Santiago, I hate the rides up there, so she travels that route once in a while, she never had to wait more than 15 minutes to get the next bus from St Dgo to Santiago. this part costs US$7.- per person.
*** count on an over all 7-8hrs one way ride, the busses are o.k., comfo, bring a sweater, the A/C's are usually working on all they can, it is freaking cold in those busses.
keep one thing in mind:
you can do the bus ride only the same day when you arrive early morning in PC.
in case you arrive in the afternoon you should take an overnighter in Punta Cana and leave for Santiago early morning. i guess you travel with luggage, so keep that in case of size and weight within the limit which you alone can carry around, lol. there's no problem to bring your luggage on those busses, that's usual.
in case of an overnighter count on a US$ 30-35.- one way rate for a cabby to bring you from the airport to a Motel, around US$ 45-65.- per room per night including breakfast for the overnighter, in the morning an other US$20.- for a cabby to the bus station at Friusa(if you choose a Motel at the local punlic bus route you can grab that one for US$1.- per person to the station at Friusa.
i travelled this Island nearly completely by bus, not at once of course, but most routes, it is no prob to do so when used to travel in a Latin country by it's public services for long distance rides.
if you never did such i would not recommend it unless you have some good spanish basic skills to come around.
during daytime the stations for the long distance rides are very crowded, so a non experienced non spanish speaking traveler with a bunch of luggage may get a bit stressed. it is absolutely usual that everybody wanna get the next seat on the next bus, ha ha.
happy travels
Mike