Good to hear you had a relatively good shake down.
TVs, unless you want to vent steam the dealer had nothing to do with the televisions installed in your coach. That was a Thor decision. In my Challenger I got 2 Seiki TVs (living area and bedroom) and a Continu US (outside). The outside TV includes a QAM tuner and I replaced the living area TV with a 46 inch Sharp.
Sound Bar - sound should be coming from the bar, and possibly a sub-woofer, directly when it is turned on. You may have to set the audio output on the TV. Sound will not come out of the speakers above the couch since you do not have a surround sound system. The reason I say possibly for the sub-woofer is that Thor informed me that the sub-woofer was removed from the 37ND in 2015. The electrical diagram also shows the electrical outlet for the sub-woofer was removed in 2015. Low and behold when one of the cats got under the couch, during the retrieval process I found the sub-woofer plugged into the electrical outlet under the couch but not connected to the sound bar. I will have to remove the TV from the wall to fish out the audio wires for the sub-woofer to connect it to the sound bar. That for me is an extremely low priority right now.
MPG - I get between 7 and 8.5 depending on speed, roads, weather and the amount of metal in my foot on any given day. The 80 gallon take makes for a nice cruising range but can be a total shock when you pull into a station that has premium only for one reason or another.
Enjoy the ride. We are on the 3rd season with our Challenger and have enjoyed every trip.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054