You can get the proper regulators at an RV store.
IIRC, most RVs are something like either 10, 18, or 20 PSI regulated at the bottle for the internal system (i.e. any heaters or inside stoves - the main regulator steps down from bottle pressure to one of those PSI numbers depending on size of camper, manufacturer, number of appliances, etc.)
You will need to find out what your stove takes as far as inlet pressure and step down to the appropriate amount.
Most gas grill regulators come from bottle pressure (@ 250psi) to about 7-11" water column (roughly 1.7-2.5 psi).
Thanks for the info! I'll do a little more digging as I thought the regulator at the tanks was dropping it down to final pressure (under 1psi as you mentioned), that's why I thought I could go direct from the quick connect hose to the stove with no additional regulator. Note, 27.7" water column = 1psi. So does each appliance then have it's own regulator to drop down to final pressure?
I found a little info on some RV'ing sites that have mentioned doing what I'm thinking, but they talked about getting the fittings made at a propane "store" and they did not use an additional regulator.
When I was working with RVs, one of the issues was that the fixed stoves, etc., were made to operate on higher pressures, because unlike a grill, where you might have maybe a foot of rubber hose between the regulator and the burner, you might have 15-20 feet of tubing between the gas bottles, etc.
So the stove inside of an RV will generally need a higher pressure supply than just "grill regulator pressure."
What I would do in your case is get a dual regulator set-up with a "T" where one regulator continues to feed the inside appliances as normal, but there is a switch or second fitting so that you can use a grill regulator as well, outside of the camper, to use your Coleman stove.
Keep in mind that Coleman back in their heyday in the RV world did lots of dicky things to make their product harder to use universally, so you may need to find an adapter or different thread style for your Coleman outdoor grill to hook it up properly. IIRC the ones we had left over at the RV store took a different threaded fitting.