[DarMar]

Welcome Jeff.

We have the portable progressive as well here but have already changed out our toilet to a Dometic 310 model.
A new seal will get you going for awhile but it seems with the Tetford toilet it's a constant battle to even keep that seal sealing for very long. Another thing I would do is add an inline water shut off right away behind the toilet as it will come in handy in an emergency or when changing the toilet out.

You will find a great wealth of knowledge here.