It is easy enough to replace the speakers...one of the very first things I do when I get a new camper.
The outside antenna...not quite so easy.
My current 5'ver, the radio antenna was hooked up to the roof TV antenna, and not only didn't work, but was also shorting out the TV and cable signal to the TV in the living room.
Once I discovered the problem, which my dealership had no clue how to fix, I finally did it myself.
For now I have a marine/boat antenna inside the entertainment center and it is OK, but do plan on mounting an outside roof mount antenna.
Although, I may not bother as I hardly ever use the radio for anything other than running the TV sound through it.
I usually only listen to the radio when outside and I find my Sony boombox with built-in subwoofer much better than those cheezy Jensen marine speakers that come from the factory in RV's.