Hello Rudi55,
I believe you can extend the layout width to accomplish what you need.
1) Set the layout width in the editor to what you need (ignoring the fact that it extends to the right).
2) Place the building objects & the player where you need them to be in the editor.
3) In the event sheet, under the "On start of layout" event, use the "System --> Scroll to object" behavior, setting the object as the player.
The scroll to object behavior will then move the "camera view" to the player on the right side of the layout while keeping the buildings to the left of the layout.
I hope this helps you.