RPOD 177

If you're 6' your options are to sleep on your side curled, on your back with your knees bent, or diagonally. Part of the trade off in making the R-Pod lighter was to make it narrower and that resulted in a short bed.
The furnace. Not a good idea to have too much under the bed. You want a clear flow of air out and you don't want anything to get too hot. We keep things there, but back and behind the outflow vent. And yes, it's noisy. We don't use ours when we're sleeping, but we've never winter camped. It might get into the 30's at night, so we get the pod warm, dive into bed, and fire it back up in the morning.

Your Yukon probably won't notice the pod behind it. My 6 cyl Silverado definitely does.

177 has been a great floor plan for me, wife, and dog. Wish it had more storage though (179?)

I am 6', she is 5'6", we have two dogs around 65-70 pounds each now.. we can make it work.. LOL.

We normally just use a small ceramic electric heater, unless boondocking, which we don't do much in late season/winter.

I have a 177 . The mattress is not very long, you should absolutely lie in it before buying!!