I've never booked an inside cabin (wife wouldn't hear of it) - but I've always thought it was a good idea. Why not book the cheapest inside cabin? It's often less than half the cost of a mini-suite - and you're never in the cabin (or shouldn't be) except to sleep, wash or change? Spend what you save on deluxe onboard indulgence and excursions. I don't see why that wouldn't work...