Hi d-mac,
We stayed at Coulter Bay Rv park with a GMC x-cab/shortbed, and a 29'10" travel trailer, where our total length was about 49'. It was TIGHT. Let me explain. While the length of some sites are certainly long enough for me (with the truck/trailer set up i had) and you, the key is the TREES. The entire RV park is under the pines, smells of pine (which is great!), and can be tricky to pull into/out of your site. I struggled both ways due to other sites and their rigs and/or trucks being at the edge of their site. As you know towing, sometimes you need to swing out to pull in. Hard to do here.
So while I can't comment on 52' length you have, maybe call the management office and ask about the length.
For other rV parks, the Fireside Buffalo Valley RV park on 26, just east of Moran might do. Still an easy drive to Tetons. Also, there are parks around Jackson WY to the south.
With our current set up (Class C) I know I could get in/out okay, but still, the trees make it tight...but WORTH it !!!!!!!!!!!!!!