First thing, congrats on the new Georgetown and
to the Forums.
Cab heat is marginal at best. When it's real cold it will keep you from freezing but you're never really warm. Unless you use the heat back in the coach, the front feels like you're pulling the cold air forward.
Our AC is ok, we generally use it along with the Dash Fans.
I've read where some people have added a curtain across the coach to seperate the driver and passenger seat from the rest of the coach. This creates a smaller area to heat or cool.
Dash fans, we use ours in the oscillating mode so it blows across the window as well as back towards the center. This works well when the sun is directly in front. It keeps the area from feeling like an oven.
Can't say much about your situation with the radio since ours only plays up front and has no speakers attached other than the two just above the driver and passenger seats.
We use the coach AC if there is anyone traveling with us and it gets too hot, otherwise we just use the fans back there to vent the heat outside. We have 2 Fantastic Fans with Covers on the roof. They operate by a built-in t-stat.
We've recently started adding window film to the inside of the bedroom window. Roll up shades is not an option for us unless I remove the day/night shades all together. We bought black window film at HD and it really makes a difference. We already have the tinted windows and with the film we're still able to look out but the light coming in has really lessened. Prior to that we had a towel clipped up to the valance to keep the bedroom dark.
We added a Playstation 2 to our rear TV for games as well as DVD use. We still have an analog TV in the bedroom, [ they changed to digital TVs about 6 months later in the bedrooms]. We have a closet next to the TV. I just fed the cables into the same hole where the power cable comes out.