So you already camp, but you'd see this as an upgrade to your camping, something that'd help your wife enjoy the trips more, something that might mean you'd take more frequent trips, right? I ask this because I've occasionally heard of people buying campers FOR THEIR FIRST CAMPING TRIPS and discovering that they dislike camping. That's an expensive mistake.
Also, you're not talking about borrowing money for a camper, are you? This is a luxury, and you never borrow for luxuries.
Buying used is a great idea. Plenty of people buy these things, thinking they'll use them constantly, and then after the initial honeymoon period, they just sit in the driveway. Some things probably shouldn't be purchased used, but campers are probably near the top of the "good idea to buy second-hand" list.
Could you borrow -- or even rent -- a camper before you make the investment to buy? It'd be great for you to be able to try a number of sizes and styles before you take the financial plunge yourself.
My husband and I are interested in a buying a teardrop camper once the kids are both out of the house. They're much less expensive than full-fledged campers, and we think it'd be a worthwhile investment for us. We're middle-aged now, and we like camping but also like the idea of sleeping on a mattress! Since you're handy, you might even consider building your own teardrop.