Provided you use fairly small boards in the loft (there are little flooring panels which are easier to get through the hatch, I can just about manage to carry an 8x2 into my loft, but it's hard work), an amusing trick is to paint the JB and cable runs on the flooring, then later, take them up to lay extra insulation, and put them back in different places.
Hours of fun.
Hours of fun.