Casen, South Haven, has a 25--no portipotty.
We have always slept well, including in AK, with good sleeping bags, and some insulation on the sides of the hull of the V Berth area. We use cheap back packing pads from Wal Mart, both under the cushions and along the sides of the V Berth.
We changed out our Caframo fans to the "Maestro" model. It moves up to 225 cu feet per min, has a variable speed control, 3 blades; there is a remote control, we put over each berth, so easy to control. There is a white, and a red LED light--perfect for reading or whatever... Ours are mounted right up the the corner, infant of the bulkhead between the main and forward cabin--so some of the air is drawn from the cabin.
When at a dock, we run a 110 volt cube heater at low or high, depending on temps, and it will heat the boat very well. We never left the Wallas running all night. First one up (usually me) started the wallas in the AM.
If I was going to run another fan in the main cabin, it would be up forward, to bring warm air down--We use the Fan-Tastic "Endless Breeze" fan. It uses 1.1 amps in low mode, and moves a lot of air. This is the same fan used in the "Vents" of RV's. Just keeping the air circulating in the main cabin, is a great idea when heating. We also us this fan in the fore hatch on warm days, when we are not using air conditioning.
If you are planing to use the boat all winter long, then install a dedicated forced air heater--such as Espar, with ducting to the V Berth--I still would have a good sleeping bag!