If you're car camping and loading stuff on a raft, size and weight aren't an issue IMO. Running out of fuel (and dealing with the hassles of pouring white gas) is not worth having a small profile in the trunk of your car. You want to boil 5 quarts of water in 10 minutes, or whip up dinner in a 16" skillet; not cook a 10oz freeze-dried stroganoff package.
Go with a refillable propane 5lbs tank and a 'tree' to hook up to your stove and your lantern. Make sure you get at least one burner in excess of 5K BTUs - Costco actually has a nice 2 burner stove on sale right now. That set up will cook big meals& provide light for 3-4 days without a refill. And you could even run a separate gas grill off that tree....and I know you do like to grill. Regardless, stay away from those disposable green propane canister- they're wasteful, have a short burn rate, and are totally expensive in terms of $/gal of liquid propane. There's a place on 38th in Denver that sells small tanks (5lbs or 10lbs) for cheap, and you can get them filled on Arapahoe in Boulder for about $7.
Now, if space in the trunk is at a premium, this could be a cool option: Cabela's -- Coleman® Signature Series All-in-One Cook System
I like the idea of slow cooking a pot of chili while on the river for the day. Still get the small tank and hose, though.