I'll just add that storage space isn't the only restriction -- big gas Class A's often have limited weight capacity for passengers and cargo... depending on what options you got (like a higher capacity chassis) you might find you only have 1500 lbs of occupant + cargo capacity, which won't go far especially if you plan on filling the freshwater tank (70 gallons of water weighs nearly 600 lbs).
There will be a sticker with the weight info, including OCCC. The best way to know if you're overweight is to load it up, then take it to a scale (with all passengers) and get it weighed, pay attention to axle weights too.
I'd take as little as you think you need, leave the rest in storage, then come back in 6 months and dispose of it.