I think the easiest thing to do is to have a sort of "trailerport" that extends from the building on the appropriate side to have the Airstream door facing the building, and to put in power, water and sewer connections. This is a "someday" dream of mine, to own property at high enough altitude that I can escape there in the summertime, with a similar setup. Whether or not the pad needs to be covered depends on the weather where you're building it... if it's in the mountains and you're not using it in the winter, you can get away without a roof over the parking area. At the beach I suspect it would be worthwhile to keep the sun off the trailer as much as possible.
Il Carriaggio — 1975 Argosy 24 | Il Progetto — 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. — Sir Winston Churchill