I have the "deluxe" system. It's an amp above the cabinet that drives a subwoofer, and they upgrade from whatever speakers they otherwise would have used to all Sony speakers... but I don't know what comes with the basic system. I figured, if I'm ordering a new trailer, I might as well amortize the cost of all the stuff I wanted into the financed total. I don't know if they use a different model of stereo, but the stereo in mine has AM/FM, DVD, and you can select each of 3 speaker areas independently (or enable them all) for the main cabin area, the front bedroom, and the outside speakers under the awning.
I think if you're watching an antenna TV feed, the audio is, by default, just coming from the TV speakers (I'll have to look again at the wiring from the TV). If you're watching a DVD or other input to the TV that goes through the stereo head unit first, you'll get the audio from the stereo, thereby playing through whatever speakers you have selected to be active.
As far as Eclipse making it easy to get to all the wiring... I'll have to look closer, because, while they could have just installed easily removable panels with quick fasteners, instead they try to hide the fasteners & access & make it look like it's not a trailer... I might replace some of this stuff with quarter-turn fasteners (like Dzus fasteners) to make it easier to get to wiring & change things up down the road.
I'll take a few pics of mine this evening & post them up for you to see if you can tell the difference between "deluxe" and whatever they offer as standard equipment.
TH: 2014 Eclipse Stellar 27DBLG, grey, Abyss pkg, 10K GVWR, ordered 6/1/13, delivered 12/14/13
TV: '04 Suburban 2500 LT, 8.1L, 3.73, 4x4, 10K tow rating, Blue Ox 14K hitch... aspiring to replace with a diesel 1-ton
Toys: '13 F800GS, '09 KLX250s, '05 DR200se