Screenhouse

Go for it!  $50 is much better than 5x or more that that amount for basically the same thing.  The only thing you may not like is the gap between the Pod and the screen house to allow for the Pod door to open.  You may get a raindrop or two on you if it's pouring.  

i use both an awning i built for the pod and a screenhouse. i would suggest proubly alittle better one than the 50$ one at walmart. the 90$ones at lowes or homedopot are better mde than the walmart ones. will last thru stronger winds that kick up. good luck

Thanks for the reply's you guys. Now I know I'm on the right track.  I bought the Walmart one(Ozark Trail) and will give it a try this summer. I think it has flaps in front and rear so can set it outside the door but will set it up before I leave on a nice calm day if there is such a thing in the Rio Grand Valley. Seems like wind pretty much every day. Once I get it up, then I can test it in the wind. Input online was good and I noticed some folks here have used the Ozark shelter in the past. If it dies an early death, I can always upgrade to one of the others you have suggested and still only be into it for a realistic amount. 
Happy trails
Hope we meet on the road.
Doug

Thanks for the info. I haven't set it up yet since we've only had a few non windy days and I'm still busy setting up the inside plus doing other "fun" things here in RGV. Park is winding down so activities are slowing down for the season.
One of the ways of using the Ozark would be as a stand alone next to the R-Pod. Do you set it up outside the door ala R-Dome?  I read somewhere that an inventive individual modified the Ozark and attached it kinda like an R-Dome. Since I have never seen a Dome set up, I have no idea how to do that. I'm sure I will eventually come across someone in my travels who has done that and could copy it.
Safe travels
Doug