There are 2 ways to do it;
1. The way I did it in both of my earlier Bitsy games was to create multiple rooms, position the objects in different places in each room, and then link the rooms together with exists so that the objects look like they are moving but you're really just changing rooms. In fact the side-view scene with the bus in this game is achieved with that method.
2. But I decided to try something different, for the most part, with this game by directly modifying the game's javascript code. I set up a "step" variable which increases each time you move, and I change the position of the room's sprites according to that step value with each step. It turned out to be quite a usable approach for achieving a large number of pathed objects across many different rooms.