I went outside and looked at the installation again, and see that really, the lip the door slides down behind is more like 2 1/2" deep. So, even if a bit of bedding gets in the way, it'll still be down 2". I think what I'll do inside is put another piece across to keep that bedding away from the slot the door slides into. It's tall enough that I think it will work.
The flashing is going to be added to the door as soon as hubby is able to work out there again (he's had an operation and is in the hospital, he should be home soon but won't be working on things like that for a few more weeks). There's enough room where the door slides to accommodate the flashing.
I do like the spring idea, maybe that could be added, but I'm really hoping to add an automatic door closer thing out there, either based on what Nifty and others are working on
in this thread or I'll save my pennies up and buy that nice one from Foy's. Yea, I know, it's spendy, but I like techie things, that appeals to the geek in me