This RV park is cramped. I would find a site that has a length that is within the maximum length of your tow vehicle AND trailer if this is your scenario. If you can't fit within that length, expect to park next to your trailer or at the front/back of your trailer. This is what I have done several times with no issues. If you have a Class A/B/C motorhome stay within the maximum length listed for the site to ensure you fit. If you have a toad, you need to factor that in as well. In your scenario, I would try to find something that's 50ft or longer (33ft trailer 20ft truck), otherwise expect to park next to your travel trailer or at the end of the site. I hope this helps.

The sites at Colter Bay RV Park are long enough (with angle parking for the truck). We parked there with a 30ft Airstream pulled by a crew cab F250. The issue is the road down each row. They are not much wider than the sites themselves and turning into your site can be challenging. 5th wheels have it easier than travel trailers due to turning angle. If you take it wide you can get in but it may take some maneuvering. Once in the reward is a spectacular view of the Teton range across the lake and easy access to the NP.