If the temp is just below freezing, no problem what-so-ever. Just shut off, disconnect, and drain your fresh water hose. As soon as it gets back above freezing, you can reconnect it.
If you keep the inside of the RV at a reasonable temperature, a few hours below freezing outside will not freeze up the pipes/tanks in the RV.
2016 Ford F350 Turbo Diesel SRW 4x4
2017 Grand Design Reflection 297RSTS
2013 Ford F350 Turbo Diesel SRW 4x4 (Destroyed by fire - 8/29/16)
2014 Grand Design Reflection 337RLS (Destroyed by fire - 8/29/16)