To answer what I want to do; we are planning a remodel of our house. First we want to 3-D plot the floorplan so we can straighten the floors (leveling the floors will probably be too expensive), then we will be using it to install cabinetry, windows, doors, trim, built-ins and anything else that one does in remodeling, including moving walls, removing walls, installing walls and demolishing the bathrooms down to the studs. Yes, we have a crawlspace.
We probably need one that lays out a line or perpendicular lines, and has a distance of 30' or so. The long measurements of the house are 47' by 31'.