Hey Howdy Hey Angela and welcome to planDisney!
Walt Disney World Resort Transportation can be viewed as an attraction outside of the parks depending on which form you take. This transportation is complimentary and can get you almost anywhere you want on the property. Knowing the details of where they run will help a ton to make your trip more efficient. Let's go over some options so you can better prepare for getting from Disney's Port Orleans - Riverside to the International Gateway entrance for EPCOT.
While you can find direct transportation from any resort to any theme park, the International Gateway is located on the backside of EPCOT. If you wanted to get there from Riverside, this might take a couple of trips. You would have to either take the boat to Disney Springs or a bus to another park and then hop on a bus to head to Disney's Beach Club Resort. Once there, you can walk through the lobby and the back of the resort will get you to the walkway to International Gateway. Just look for Disney Skyliner which has a loading station at the entrance!
If you were looking for a more direct way to get from one to the other, you may want to consider either a rideshare or Minnie Van.
Minnie Vans are Disney's rideshare option but you will be getting from one place to another in style. Operated through the Lyft app but run by Disney Cast Members, these vans are unmistakable for getting you to your location efficiently and with the Magic of Disney. Either of these options would come with an added cost but would be the same pick up from Riverside and drop off at the Beach Club.
Depending on your urgency to get from one to the other, you have a few options to consider. If you have any other questions feel free to reach back out and let us know, we are always happy to help!
To Infinity and Beyond,
Nick