Flight
There are several direct flights from the US to Cartagena. You will want to fly in to Rafael Núñez International Airport, don't forget your passport! Make sure you have the address of where you are staying (hotel, Air B and B etc) for the immigration officer. It is about a 15-20 minute car ride to the walled city. Yellow cabs are the easiest method of transportation. As soon as you exit the airport there is a designated section with yellow cabs. They charge around 15.000 COP (approx. $4.80 USD) to get to the walled city. Make sure to always ask the price of the ride before starting your trip! You can also book private transportation here: http://eventos.aviatur.com/victoria-y-sami/
Hotel
A travel agent in Cartagena put together a list of hotel options you can choose from. Our advice is to stay in the old city (ciudad vieja) so you can be walking distance from everything! At this link you can also book transportation to and from the airport to your hotel!
House Or Rental
Air B & B rentals are a great option in the walled city, outside the walled city there is also great options as long as you're ok with taking a taxi into the old city for wedding events!
Hotel
This is a great low budget option in the walled city!