City Water Intake and Quick Connects- dust cap?

This is my first post, so here goes. On my 2005 R-Vision MaxLite TT, I have the typical city water connection on the outside. I'd like to insert a "quick connect" connector to hook up water quickly. Problem is, if I leave the male end of the connector in the city water connection inlet without a dust cover, it will get dirty from exposure. The standard white rubber dust cover for the city connection by itself does not fit the brass quick connector.
I have looked for a similar dust cap (preferably with a lasso so I don't lose it), and haven't seen any that fit. Does anyone have a solution, or found a dust cap for these quick connect fittings? I have both the brass style and the Melnor brand plastic style fittings. If I can't find a way to protect the quick connector, then it seems pointless to have it on my city water inlet.
I was unable to find any previous posts on this topic.
Thank you for your help!