[ThePair]

I think it all depends on your use and desires. If you have and use the Thetford recirculating toilet, and if you think you are going to run into a use situation where additional black tank capacity would be useful, then the "long pipe" redo makes the most sense to me -- if you're going to do it, you might as well DO it. Also saves you from carrying around a tote you may or may not use. That being said, some have been able to fit a tote on the spare tire rack behind the tire, so it's there if you need it and out of the way if you don't. Again, different use model.

If, on the other hand, you don't have that need (toilet swapped for another model, don't stay long enough to need the extra capacity, etc) certainly a local "cut/paste" to add a Y connector is a lot less work.

Our toilet was swapped for a Curve (cassette) partially because we, too, had the separate dump outlets, and also because I felt the cassette would be an easier use model for my family than the recirc.