I am 28 and still going to the peds group (My doctor wants to hang on to me until I finish grad school)
They have a large peds group with a lot of Crohn's specialization. Dr Wyllie is regarded to by many as one of the best in the world. When I got sick in California, the panel of docs that saw me were arguing in front of me over who got to call him to consult. He developed the most widely used textbook in peds GI with a few others in the department.
http://www.amazon.com/Pediatric-Gas...=sr_1_1?s=books&ie=UTF8&qid=1370635393&sr=1-1
Their nursing team is absolutely fantastic. If you are having an issue between appointments you can call the nursing line. They will then work with the doctors and you to see if they need to adjust a treatment or schedule a response appointment.
They have a really nice procedure and remicade suite too. The kids get the procedures on the peds GI floor.