Sprinter Carrying Capacity

nitecapt wrote:
his is all good info......I think the Galleria Coachman has a large capacity but they are SOOO expensive

That's a Class B van conversion, and it will have more OCCC than a more heavily loaded Class C, on that basis. If you're after a Class B van, then OCCC is far less of an issue. You mentioned a Thor Class C in your original post, so most of the comments so far have been based on that.
The Galleria will (probably) easily carry 4 adults with full tanks, because it doesn't have all the amenities that a typical class C conversion adds to the Sprinter cab chassis. Might be a little crowded in the class B van for 4 adults, though.
The differences between a B and a C are significant to some, and not a big deal to others. It's up to you, and you're right about pricing. Some of the class B vans are more expensive that their class C counterparts. They often have extra "techie" stuff added that can drive up the price.
If you want to be able to carry 4 adults, all their gear, have full tanks including propane, and tow something as well, you will probably have to look at the Ford E350/E450 chassis. It's more robust, but it has it's flaws, too. The fuel economy with the standard V10 6.8L gas engine is poor, even if paired with the 6 speed transmission, no matter what you read on the forums. I know, I had one in the F53 chassis of my Sunstar.
There's supposed to be a newer Ford chassis/engine/transmission combo coming out sometime soon. You might want to take a look at that before you buy. Some have said it gets better fuel economy, but physics is physics, and you can't create extra power out of nothing. It takes gas to push those pistons and create that power to move the weight of the vehicle and cargo, and that will probably cost you more to travel from A to B with the Ford, than the same route in a Sprinter based motorhome. RPM ranges for torque and horsepower on the 2 types of motors being the main reason for the differing fuel burn rates, but that's the oversimplified version.
As others have said, YMMV, but it's pretty much a done deal, when you compare the two main chassis manufacturers. Diesel is not twice as expensive as gasoline, at least near me, so that common argument is rendered invalid. There was a time when diesel was cheaper than gas, but now they're usually not that far apart. In fact, here in Ontario, you'll usually pay a little more for a litre of gas than diesel. Thanks to carbon taxes?:E