How often do you RV? This dictates what you are willing to spend on RV tv.
Most streaming requires broadband internet, and the park provided stuff has smaller data use limitations. You can get HBO and AppleTV programming through your cellphone internet, but I am fuzzy about getting this onto a big TV screen.
I fulltime and use Dish Network, although my 200 channel package costs me about $130 a month now. I use a tripod dish that I aim on setup that works with my dual tuner receiver. I looked at the San Diego Craigslist this morning and found this new in box Tailgaiter antenna system for only $100, although my receiver is not compatible with this antenna.
san diego for sale "dish network" - craigslist
sandiego.craigslist.org
On your speakers issue, is your trailer fairly new?? There have been all sorts of Audio Visual Systems wiring problems reported by new unit owners on this forum. There seems to be little or no quality assurance checks of these systems at the factory. This may be a warranty issue.