Usually if you're drawing a floorplan you use arhitectural units and draw in feet and inches, AutoCAD considers one inch is one "unit". Something going off the screen is controlled by how you "zoom" into the view. By changing zoom you can view millions of units acroos a screen, or 0.000000000001 unit. Try a "zoom" "extents" to view all linework. You may want to change your "limits" to be greater than work area but to me limits are not useful, other than to allow "grid" to be used and to "zoom" "all".
You can plot in any scale later, by setting plot scale during plot. Preferred method to set plot scale is by setting the viewport scale in paperspace.
You do want to consider plot scale for any text and dimensions placed so they will display properly. you usually want text plotted at least 1/8" tall, which is 2' high for the 1/16" scale.