Mich F,
For full disclosure, while your OCCC number looks good, from a CAT Scale slip you once posted on a different forum, you only have about 1,800 lbs. capacity on your rear axle. Almost 900 lbs. of your OCCC is unusable unless as rjstractor says, you hang a lot of stuff off the front bumper. (To piggyback onto rjs comments, when you put weight behind the rear axle, it not only adds it's weight to the rear axle, but the rear axle acts as a pivot point and it takes weight OFF of the front axle and transfers it to the rear axle too. Think of a see-saw.) A couple could probably live with that if they're careful about weight. But I think a family would be hard-pressed to keep it within the limits. But it really depends upon your intended use of the rig.
c5er, when we were looking for our first RV for our family of 6 back in 2004, we looked at the E-450 based rigs, and anything large enough that would comfortably fit the family the way we wanted to use the rig, would be WAY over weight. I estimated we'd need about 3,000 lbs. for water, people & stuff. That estimate seemed to be pretty accurate based upon various CAT scale weight tickets I've picked up over the years. The "Super C's" on the Kodiak chassis's were just coming out at that point. We found our "ideal RV" as a class A. It has a GVWR of 22,000 lbs. and full fuels, 1/4 water and me it weighed in at 18,800 lbs. So we have about 3,200 lbs. of capacity for the family and all of our stuff. Due to the axle weight specs (the rear & front axle specs actually total to over 22,000 lbs.) we have yet to load it and exceed an axle weight rating. The heaviest we ever rolled through the scales was about 21,600 lbs. And by the way, our rig is 36' long, has 2 slides, 2 AC's, hydraulic levelers and TONS of storage space inside and out. With a large family, we needed that and pretty much use most of it.
By the way, all of that research paid off. We still have the same rig today and I'm planning on keeping it for at least another 5 years, maybe longer. So moral of the story, do your research first. It looks like you're doing that, so keep asking questions here.
Anyway, try to make a real good estimate of what you'll need to carry for weight and understand that in a Class C, pretty much all of that weight will be carried on the rear axle, so excess front axle weight capacity isn't helpful.
We knew we'd be travelling and need the water tank (80 gallons) full, and I usually travel that way anyway...just in case. Some people are comfortable carrying minimal water. Some people are very good at being minimalists. My wife and I aren't. I'm a "do-it-yourselfer" so I have about 3 storage bins for tools and spare parts. I swear the wife had winter parkas stowed under the bed when we went to Florida IN JULY a few years back. You know, just in case! LOL
The only thing I'd recommend is not to rule ANYTHING out in your search. Even look at some class A's. I'd recommend looking at 5-10 year old Tiffins, Newmars and Winnebagos. They might seem a bit more intimidating, but driving one isn't any more challenging than driving a C. But STILL be vigilant with weight ratings and actual weights. KNOW before you buy!!! :)
Good Luck in your search.
~Rick