I finally watched this episode last night, and it was decent.
The Squidward/Bubble Bass dynamic was interesting, and the train/hotel/city settings were really well designed. There were also some really funny jokes (the baby, the fondue, Old Man Jenkins's plane). However, I'm not the biggest fan of the ending where both of their conventions get destroyed for no reason. It just all feels kind of underwhelming; in my opinion, it would've just been better for both Bubble Bass and Squidward to just go to their respective conventions and have a good time. But I guess watching the muscular lady and her muscular baby chasing Squidward and Bubble Bass into the horizon does kind of make up for it.
Using my old 20-point rating scale, I'll give this episode a Decent (12/20). It's not the best that Season 14 has to offer, but I appreciate the writers for exploring a new character pair.