I just looked online at a couple 2015 305RL's and I see that they have a bumper, which mine doesn't. I also see a 2" receiver so I assume the OP has that set up. I see 3 options.
1. cut off the bumper and remover the receiver and fabricate a cargo deck system. While it sounds like a fun project to me it might be more than some would want to take on
2. use the 2" receiver with a cargo deck that works with receivers. I still have one of those that I used for years on a previous 5er. I just put it on when I needed to haul something on it.
3. same as above but also add a folding hitch adapter so you can leave it on the trailer full time if that's your preference. Add a couple hitch locks as well to stabilize the set up and it would work quite well
https://www.amazon.com/Goplus-Foldin...5422809&sr=8-3
https://www.amazon.com/Tightener-LIB...NsaWNrPXRydWU=
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Jeff & Sandi (and Teddy - 7lb Schnorkie)
2018 Montana HC 305RL / HW Progressive EMS
2015 RAM 3500 Laramie Longhorn Crew Cab 4x4 DRW / Demco Recon Hitch on RAM Puck Ball