Big Steve,
You pretty much stated that you'll need a 30' to satisfy your space needs, so why would you consider something smaller? Do you want to be unhappy 99% of the time you take the rig out just in case your 30' rig doesn't fit into a spot on a campground you might visit sometime in the future?
Most here will tell you, it's all about the floor plan. Find a floor plan that will work for you and your family. You'll adapt to whatever else you need to do.
As others have said, there are plenty of campgrounds around. We tend to stay at mostly private campgrounds and have never had a problem finding a site to fit our 36' class A. In fact, most times, we have our choices of sites based upon where we want to be located in the campground and/or available hookups.
The only thing I'd mention, seeing as you're somewhat of a newbie, is to understand that ALL of these RVs have weight limits. Just because there is enough space to bring things, doesn't mean there is enough weight carrying capacity. Some people run their rigs overweight all of the time and it doesn't seem to bother them. Me? The engineer in me makes me want to keep things under the limits set by the manufacturers. I'd recommend you at least consider weight as a possible issue. Just two people in a 30' Class C probably won't be a problem. A family of 5 or 6 in that same RV is a different story. But my recommendation, know what the limits are on any RV you consider and feel free to ask any questions which might arise.
Good Luck in your search!
~Rick
2005 Georgie Boy Cruise Master 3625 DS on a Workhorse W-22
Rick, Gail, 1 girl (27-Angel since 2008), 1 girl (22), 2 boys (23 & 20).
2001 Honda Odyssey, Demco Aluminator tow bar & tow plate, SMI Silent Partner brake controller.