I just successfully ported a Tracfone on Verizon's network to a new (to me) phone on Page Plus Cellular.
I used the porting page on Page Plus's website, for free I might add.
For the account number I used my Tracfone's MEID (easy copy/paste from Tracfone's website since I had it registered there) and the last four digits of my phone number for the passcode.
I also entered "Tracfone" for the current carrier and in the comments section entered "from Tracfone on Verizon network" since many Tracfones are on AT&T's network and the porting process is different internally. I figured I would cover a possible problem before it arose.
After waiting around three hours, I tried calling the number and got an error message. I then dialed *22890 on my new phone to activate it. I then made an outgoing call on my new phone to finish the activation process with Page Plus as per the porting instructions.
All in all a more or less seamless process. I would have liked an email telling me the process was complete but I can't complain.