I would like to relocate or swap my upstairs bathroom with the laundry room that is on the opposite wall. More or less flipping everything to make a mirror image just in the other room. I'm sure it less to just update the current bathroom, but the other room is larger and has a window. I am wondering if this would be a costly undertaking.

Bathrooms these days are never cheap because people want tile showers with glass, heated floors, and lots of custom work.
But assuming that the plumbing is accessible (preferably underneath as well as in the wall) and you locate the toilet near the stack, and all or most of the plumbing along that same wall, that will cut out some expense. Tubs are often set in concrete and have to be broken up and thrown away. You need an exhaust fan and new fixtures. You could spend at the very least about 7K (no custom shower) and easily 15-20K, paying someone.

Yeah I don't plan on heated floors or anything like that... don't really need that here. I know the current tub is just an all in one surround and everything is builder standard... aka cheap. I am placing a jet tub/shower combo, and plan everything along the same wall to hopefully make the plumbing easier.