Porting out of Tracfone seems as simple as porting from anywhere else. You do need to talk/chat with customer service to get your account #.
Plus, there's a bonus, but you need to confirm it with CS before commencing: I have twice ported out a number from a Tracfone line, and kept the balance and service days by promptly reactivating the line with a new number. In my limited range of experience, Tracfone and FreedomPop have been the only places I've been able to do this.
(I first talked to customer service via chat to confirm that I could do so, and had a transcript of the chat emailed to me. One time I needed no assistance from customer service to reactivate the line with a new number. The other time, I needed customer service to assist, but it was easy enough with the chat transcript assuring me that I could do so.)
(EDIT TO ADD: I've also ported numbers in to Tracfone before, and never had an issue.)