Just in case, have you seen this handy
Blow Out Hose?
Hook it up to an air source, connect it to the public water inlet on the camper, set it to about 30 psi then go around to each faucet until they're only blowing air.
While I do this I'm still concerned about any water that's in the pump itself or the accumulator tank that can't be drained or blown out so I generally add enough pink stuff to the fresh water tank just to protect the pump and accumulator, as well as drain traps. Considering my FW tank is only 20 gallons I save that for washing and drink bottled so any left over taste isn't an issue.