A creeper works OK under the lowest parts on the fuselage but it’s not quite high enough to reach the bottom of the wings without doing a continuous sit-up. There are adjustable height creepers you can buy but they're kind of spendy. Since I’m frugal (cheap?), I put together a DYI solution by building some lifters that can be added on top of a standard Harbor Freight creeper to adjust its height (see photos below).
It makes doing the bottom of the plane a little less painful
