Back on 10July2015 I got a replacement locking gas-cap for the our Vegas 24.1 (E350) from American Auto Parts of Lincolnton NC (a NAPA parts store). It costs $19.22 and had the part number BK 7031723.
Once I tried to get it opened without the (key was on the other key chain)...it did not give up so I drove home and got the key.
Sheree & Michael NCNG LTC(ret) with Munpi and Sheba (cat).
2016 Vegas 24.1 E350 5 speed "Ms. Enterprise", Bug-Guard Screen, Recliners, Infotainment Center, HUD, ARC Shower Rod, Safe-T-Plus, Curt SpareTire Mount,Tornado Black Tank Rinser, ext. WiFi Antenna, Roadmaster Tow Sys& Invisibrake.