If you use a whole rv filter, I recommend that you are careful about what the filter removes.  Personally I want chlorine treated water in my RV.  That would include all the supply lines but especially the fresh water and hot water tanks.  Outbreaks are rare, but I have a good friend who was hospitalized for a couple of months due to Legionnaire's Disease.  Other nasties can also grow in the hot water tank, supply lines and faucets.  Consider a sediment filter for the entire RV if you need one and use a final filter for drinking water.