Thank you, playacaribe. I think the free bag is only to certain airports/certain countries. (It says "For Blue and Blue Plus fares for flights to or from Santo Domingo, Santiago, Port-au-Prince, Port of Spain, Kingston, Cartagena, Medellin, Bogota and Lima and Mexico City: one checked bag is included and the second checked bag fee is $35"). I think POP still gets charged for first bag. I'm not sure why that is?! And STI is definitely closer than PUJ...I was only serious about wanting break up with Jetblue, not really about wanting to drive from Punta Cana-lol.
And peep2, STI is, say, 2-1/2 hours to Cabrera....just not my preference. POP is so easy...easy car rental, famously cold Presidentes, 1 hr and a bit drive, provisions stop at Playero, Gordito's taco for the road....one flat, single coastal road. I fly SDQ and STI only if I have to. I also only drive in daylight hours...so many of those STI and SDQ flights are out for me. Thank you both for your replies.