Originally Posted by switz
The fluids capacity on the 23D is modest at best with 39 gallons of fresh water but only room for 21 gallons of gray water (sinks and shower) and 18 gallons of black water (toilet). The gray water tank tends to fill twice as fast as the black water tank.
You also need to factor in the fact that the kids get heavier every day.
Doing your home work now is cheaper than signing a contract to purchase and finding out the weight numbers will not work.
I was curious what the maximum towing was on your Nissan and according to what they publish it's 6,000 lbs. Even without factoring in the weight of passengers and gear in the vehicle you're pushing that V6.
If you do decide to go with the 23d (I just purchased one myself), the grey water is the one that you need to think about. If you don't camp where there are full hook-ups (a lot of Texas state parks don't have full hookups), you will need to think about purchasing an external storage unit. We use the one we had with our tankless A-frame, but these will allow you to drain your grey water without moving the trailer.
When I purchased by first camper, I didn't do my homework. Towing it home from the dealership immediately told me that since I was near my limit, it wasn't the vehicle for towing that camper. We ended up trading in that truck and buying a larger v8 that same weekend. Fortunately, it's plenty big enough and setup correctly the Airstream. But if it was me, I don't think I would bother with the expense of adding the water cooler. You're already at towing capacity (and back in 2010 they weren't using the SAE J2807 standard and cheated a lot on towing capacity). I'm going to guess you're probably 300-500 pounds off from that figure. Which means your probably over the limit before you're out the gate. Do some checking online and see what others with your vehicle have found. I'm going to guess though that 6000 lbs is going to be past what others are towing safely.
One other thing to think about is fuel economy. When you're near max towing, your engine will have to work harder and you notice a significant drop in fuel economy. Right now, not that big of a deal, but as fuel prices increase it will be. Again, just one more thing to keep in mind.