There are times we (mostly her) have wanted a screen door on the coach but I have been reluctant to spend the time or money. Picked up a Doorway Screen Curtain at WalMart, it's 38" X 81" with weighted bottem.  Put it in today, rolled the extra length around the tension rod and snugged with tie wraps.  Cut about 9 inches off the width.  It comes with hook and loop fastners for the sides.  When not in use it can quickly be rolled up and stowed above the tension rod. Took some pictures but can't see much so won't post them.  Not for everyone but for less than $15.00 I think it will work for us, at least for a while and spring is just around the corner!