Not sure about those Extend a Stay adapters. Aren't they just a Tee fitting? If so, you're still using the high pressure source. It's a benefit to getting rid of the Coleman regulator as they don't always regulate properly - ours doesn't. Being able to plug right into a quick disconnect is so much easier physically, especially for the older generation with bad backs, arthritis, etc. (like me)....
The Coleman grille has a regulator built into the fitting that attaches to the BBQ. The thing about the quick connect under an RV is that they are low pressure while the Coleman as it comes from the factory requires high pressure gas.
If you want to use the Coleman stock regulator, then you must connect to the propane tank(s) directly before the regulator at the tank. If you have 2 tanks and one runs dry, then to keep your grill going, you have to manually move the adapter over to the other tank. Or, have two T-adapters in place at the tank. I found it was a bit of a bother to keep going into the tanks to attach the hose every time we got to the cg and set up.
It's safe doing the piping mods I described as long as you use telfon tape (except not on flare fittings) and make the connections snug. You should always do a leak test afterwards. You can use soapy water in a spray bottle. I have something called "big bubble" Gas Leak Detector made by Whitlam. Has an applicator with it and you brush the solution on. If you aren't prepared to perform a leak test afterwards, shouldn't make any gas line/equipment changes.
You should be able to find a source for a regulator on the internet. I just found some. You may not need the exact same Coleman regulator but unless you have it in hand, the spring inside may not be the correct one. If you have a good local BBQ store, they may be able to help. Maybe contacting Coleman directly will work.
srh, you should have the seal on the internal valve facing towards your BBQ and then the spring closest to your tank side. If you look at the end of the fitting on the hose, you should see a tiny tip inside. If you had the spring in place, you'd be able to push it open with a small screwdriver. If you have it turned around, it may be plugging the line closed. The fitting you want has a 3/8" flare at one end and 1/4" pipe thread at the other. Many stores that sell gas fittings should have these including Home Depot.
The only downside of making modifiying your Coleman regulator is that once you have cannibalized it, you'll never be able to connect a remote cylinder directly to the BBQ.
Yesterday, I installed a quick connect fitting at the rear of our unit right where the door to the kitchen area is. The factory original location was not in a great spot. I tested the new fitting and the new adapter and it works great.
Gil & Deb & Dougal the Springer Spaniel
2014 KZ Spree 262RKS & Ford F250 supercab V10 4x4 LB