You will never get rid of all the RV antifreeze in the system just by draining or blowing the lines out. Some will always remain just like some water always remains even after just blowing out the lines. The remaining antifreeze won't be pushed out until it is flushed out with water when the fresh water system is put back in service.
Nothing wrong with either leaving it all in or draining it as long as some antifreeze is left in the toilet bowl to protect the seal. Also leave some in the black and grey tanks to protect the dump valve seals.