for sound bar- look at sony or vizio - fairly priced and make some smaller ones that will fit under your tv- if your feeling crafty - you can move the tv up to gain more room- I replaced the tv and mount with a locking one that will pull out if need be and moved up a bit to fit larger soundbar under tv and put sub into compartment next to fire place- ill see if I have some pics -
as far as dish depends on what type you go with - for years I had the portable type and mainly used on the ladder mount- only 2x in 7 years did I have to put on ground - and with most you can have a second tv/receiver however it is stuck on the same sat as primary receiver so somewhat limits what both tv can watch- so if you are using your new trailer a lot and want better reception and ability to watch any different programming on 2 or more tvs then look into roof mounted auto unit
added pic of how I did bedroom tv-
I will get some of main tv this weekend as have trip planned