UPDATE 12/23/17: I successfully cycled across the Dominican Republic and into Haiti earlier this year and it was quite an adventure. I'm creating DR & Haiti country pages to share my experiences for each and will link them here when I'm finished.
I've decided to switch it up this winter, getting out of the Andes of Colombia and Ecuador, and take my cycling to the Caribbean. After looking at a map, I decided on the island of Hispaniola, also known as the Dominican Republic and Haiti. I love the beach, sunshine, Caribbean food and can still practice my Spanish. It's also an inexpensive flight from California.
So I have arrived in Punta Cana, Dominican Republic with my mountain bike and plan on cycling west to Port-au-Prince, Haiti, roughly 300 miles (500km) on Google maps. I cannot find much information about cycling in either DR or Haiti so hope to provide some useful info. I have seen just a few local bikes here and there seems to be no visible road cycling culture like I've experienced in Colombia and Ecuador. That being said, there is still a good bike shop, Bike Zone, in Punta Cana because mountain biking seems to be pretty popular: