I have used the wave heaters from way before they were called wave heaters with no problem, as long as you vent, they are great. The one that I have now is hooked up just the way you are talking about, coming off the stove line, a shut off valve, and a quick disconnect junction, and a indoor 6' line to the heater. When not in use the heater is put under the bed, and when traveling when we are using it, we put it under the table that is in the slide out. Works great, and you can direct it to where you want the heat.
Mike