The exhaust is the hose covered with white insulation. It exits the bottom of the heater then curves around and above before heading out through the transom. There’s a pigtail pipe just after the exhaust leaves the heater—condensation can drip out. We kept pretty much the same setup with the new unit. We also kept the existing ducts and vents: one in the quarterberth, one under the hanging locker by the nav station, and one under the drawers in the v berth.
I can post some additional photos (probably tomorrow).
Update: a couple of photos attached. One shows the new fuel pump near the forward end of the fuel tank, viewed through the undersink cabinet door in the head (I installed it by working through the removable panel in the quarterberth). The other shows the new controller mounted above the nav table. Espar's "marine kit" included an extra-long wire harness, which runs between the heater, fuel pump, and controller. It also connects to the battery, with a couple of fuses in between, via buses installed in the hanging locker by the nav station.