I have a single cartridge filter under my sink on the cold line to the kitchen faucet. Accomplishes the same function, I just did not install a separate faucet. The
RV Water Filter Store is a good source.
I figured the extra use for filtering water for dishes or cooking was not cost prohibitive to just change out the filter every once and a while. I usually change it each season anyhow, with winterization. I'm sure I do not deplete a cartridge in one season anyhow.
Brian
PS - You can drill a hole in the countertop no problem, I would use a hole saw to start and run it backwards to score the top surface first, then drill. Solid surface countertop (Corian, Hanex) is fairly easy to work with....