Hi Mike, so here's a version where I've simplified the roof to be just one slightly curved piece rather than being made up of fragmented surfaces at very slight angles to one another (see attached 3DM file):




You'll still have problems with trying to do the whole roof all at once, because of the complex corner junctures, but you will now be able to do either the front/back or left/right set of edges alone now, like this for example:






- Michael