That question can only be answered by YOUR own state (or the state that your MH is "stored" at) DMV.
Technically if is pulled off the road and never ever touches the public roads during the rest of the life of the MH in most states you can allow registration lapse..
The problem begins however the moment you pull it onto a PUBLIC road, that is where you MUST register (and have insurance also)..
Honestly there is no "savings" to be had if what you are trying to do is to "skirt around" the DMV rules..
Typically registration is for ONE year at a time so you will have to pay the registration for the year plus any required insurance and in some states to drive on public roads will also require an annual safety inspection..
Some states you will pay property "taxes" on your motor home also..
So to put this plain and simple, if you are only wanting to move your motor home on PUBLIC roads even just once during the year you most likely WILL have to pay for that entire year (no pro rated registration).