I don't think it's sturdy enough. Okra could destroy that thing in about 15 minutes (and would) and she's half the size of Rufus. He needs to run rebar through it or something; duct tape alone is just not going to hold it together in the face of a determined assault. I'm a little worried about the whole thing although I grant the possibility that Okra is just more evil than Rufus in general.
I'm sure I've mentioned Catland, the habitrail I made out of boxes and duct tape for my cat, but it had a slide into styrofoam pellets and was made for thrashing, just boxes and carpet boxes and tape from after a move. It took up a wall and shook mightily when in use, but held up just fine for months.