I have not heard of anyone putting in a pet door. I would expect it would be very easy to do. Take the lower screen out. Install a lexan panel, cut the right size hole for the pet door. Just remember, your neighbors, and how to secure the area around the TT, for them to roam safety.
Yes I did. We have the metal screen protector on inside & I left the outer winter clear plastic cover on the outside . There is a thin framed dog door that I used & just cut the hole thru all 3 pieces and attached doggy door. We keep the main door open so Toby can come & go at the farm. We rarely travel with our pets. Sorry I can't remember the maker but I think it was from Chewy