Ok, here is my .02 cents. I have banged my lions share of Costeñas (pronounced: Cos-ten-yas). NO matter what city in Colombia you find yourself, ask a local Colombian guy who the most down-to-earth, happy, and down for whatever women are of the country, and a Barranquillera aka "costeña" will surely make the top 3 list.
Costeñas come in all colors, but for the most part, they are mestizo looking. Now, understand one simple thing: They are NOT the most beautiful women in Colombia when compared to Medellin/Bogota/Cali, but they are the most fun - hands down! Even the few stunners that look like Shakira are very, very friendly!!!
This does not mean that stunners do not exist, it means they are not in ridiculous abundance as you would see in Medellin. However, the paisas will never be as friendly as the women from Barranquilla - get me?
It is extremely normal for a Barranquillera to be DTF the very same night she meets you. They are very sexually liberated and DTF - all you have to do is NOT FUCK IT UP! BY default, if she agrees to go out with you, she agrees to fuck at the end of the night unless you do something stupid to kill her mood - act beta, insecure, too much of a dick etc.
The best time to go to Barranquilla. RIGHT NOW!! Carnival is around the corner.
Here is a blog from a gringo traveler to Carnival in BAQ:
http://www.carnavaldebarranquilla.net/barranquilla.htm
I stayed in Barrio Los Alpes which is a level 6 neighborhood. I had my own motorcycle (fantastic idea to get one), so I cannot give you info on public transportation.
Mixx