One thing I'd recommend would be to find your ideal new model RV in the next year or so. Then when you're ready to buy search for that particular one that's a year or two old and you'll save a LOT of money. Also, the kinks should have been worked out by then.
Buying new won't assure you that you'll have no problems.
Study the weights very carefully for what you want to pull. You'll need to take into account passengers, 'toys' and all belongings along with full fuel and water. Many time stated RV weights don't take into account options like an awning, etc.
I'm not familiar with Class C's so can't help there. Good luck!