Great to see that someone else is doing a full monte on a Caravel!
We have over 100 days of camping in ours in the last two years and have had no problems with our Norcold N300 fridge and fiberglass replacement chimney. With the small fridge and tall chimney, we always had good air flow and didn't have need for a 12v
Be careful when you measure for a fridge. The distance between the door and wheel well is small on a Caravel
. We couldn't go larger than the N300 and, in fact, had to raise it off the floor to get the width we needed. (Wheel well arcs towards the rear, increasing the distance between door and where the bottom of the fridge intersects with the wheel well).
BTW, I really like the fact that there is no parasitic draw on this model. Some fridges require a fair amount of DC power to monitor the flame.