I have not done a head unit for the RV but have replaced several in other vehicles over the years. Crutchfield is very good with help if you call them.
As to which brand, I have had Alpine, Jensen and Kenwood. The last two that I did in my trucks were Kenwoods because Kenwood uses Garmin and I did not have to worry about the GPS vendor going out of business and leaving me with a map system that would not update. There are higher end units but I had good luck with all of the above.
The mic is not something that is hard to hook up. You have to pull the unit, of course, to get to the plug but that might be an option, unless you are just tired of it and want it to go away