If the Northern Lite 10-2 EX dry bath is like our 8-11 EX dry bath, the primary heater vent in the rear, hallway area is where nearly all the heat from the furnace exits into the camper. To my knowledge, there are no other heater vents other than a small 2" piece of ductwork (connected just inside the primary vent) which routes a small portion of heat into the basement area. FWIW, we turned on our 8-11 furnace with 20 deg ambient temps back in Feb. Took less than 30 minutes to get the interior temps up to 65-70 deg.
As for the Dometic Penguin II 10k a/c unit in our NL 8-11, with ambient temps of 107-108 degrees, it cools the interior down to 78 degrees in about 60-75 minutes. With ambient temps of 95-100 degrees, it takes about 30-40 minutes.
I believe the Big Foot truck campers use a larger furnace and thicker insulation on the outside walls than the Northern Lite. If maximum heating efficiency is a big priority, the Big Foot may be the better choice.