You will absolutely have water in the lines or low spots after dewinterizing. There is no mystery in dewinterizing, just flush copious amounts of water through the system. Personally I would not dewinterize till you are in warmer weather. If you dewinterize before leaving, you will have to partially winterize before leaving anyhow, even if if just blowing out the lines, so why bother? Just wait till you are in warmer weather, hook up to city water connection at your first campsite and flush away. If you are winterized right now, why would you take the risk by dewinterizing and suddenly a hard freeze comes one night, and you expose yourself to possible problems.
2011 GMC Sierra 2500HD
2014 Rockwood 8289WS, Diamond Pkg.