A collapsible personal wheeled conveyance comprises a first and second collapsible side frame, each having ground-contacting wheels, and at least one adjustable crossbar configured to physically connect the two collapsible side frames, the adjustable crossbar(s) having a selectively adjustable length. The adjustable crossbar(s) may be lockable or non-lockable. One or more of the adjustable crossbars may comprise seat-supporting adjustable crossbars. A seat can be configured to move laterally along such a seat-supporting adjustable crossbar to permit selective adjustment of the lateral position of this seat with respect to the side frames. One or more locking mechanisms can serve to lock the seat at a particular position. By one approach the aforementioned seat-supporting adjustable crossbar can include spacing indicia to visually indicate when the seat is centrally located between the first and second collapsible side frames for a particular selected length of the seat-supporting adjustable crossbars.