We had thought of doing that same thing, then we reconsidered and ended up purchasing a 5th wheel and leaving it in AZ. We have it in an RV park outside of Yuma, while we are there we pay the normal RV Park rates however for the seven or so months that we are not there we leave it on our spot and it only costs $25.00 per month. We have the trailer registered in AZ, costs about $275.00 per year, they base plates on model and year of the trailer, goes down each year and we also have US insurance that runs about $270.00 per year.
Hope some of this helps.