They do get very busy at the opening around 7:30 when it opens as many want to make it to international gateway. But, the line should go quickly as the Skyliner is constantly moving unless a delay happens or they are helping with anyone with handicapped situations..
Plus, this also depends on your location of your room within the confines of Pop. If your the furthest away from the 90's and 50's it will be a good 7-10 mins hike yo it plus the wait for the Skyliner line with that..
You also may have to wait at the Skyliner Hub at Caribbean Beach when you have to switch to the Epcot line there which can also add more mins to your destination to International gateway..