I just leave mine in the tank and do nothing, I do run mine down toward the end of the season. There are tank heaters to thaw the DEF if it is frozen, then decide to move the coach. I've had diesels for years that used DEF and never drained them in the winter. Think about all the diesel equipment that uses DEF from generators to heavy equipment, just sitting there till they are used again.
Jeff and Cheryl
2015 Aspire 44U, 2012 Jeep, FMCA - 476557