If money is tight then forget about hooking it up to the panel for now. HD extension cords(14ga min) will work just fine. As for the dog house idea I would cut another opening at the back for cross ventilation and possibly plug a box fan into the generator to blow air over it if it is hot out. Having somebody put an extention cord type pigtail on your furnace with a DPDT switch to disconnect it from the rest of the house is a must. If the power goes out in the winter you will be happy you did it. Don't forget that the longer the run from the generator and the higher the amp draw of the appliance, the heavier the gauge of wire in the extention cord(numericlly lower) will have to be.