Screen Door?

My husband and I took our new-to-us 2002 2720SL out last week to Cuyamaca State Park, near San Diego. We had owned a HiLo previously that had a dutch door, with a half screen. One thing we missed having on this trip is that screen door as the bugs were very active in the heat. Has anyone added a screen to the door, or know of any alternatives?
Thanks
Josi