Lanky growth is pretty common in your area, and yes, you can absolutely take it out of the pot and store it lying down. If you do so, it's best to lay it on some cardboard or newspaper.
One option (and yes, in the spring, for sure) is 'downgrafting'. It essentially means taking a section out of the main trunk and grafting the pieces back on to each other. It won't solve the problem of a lanky tree in the long run though. I'd go with the two main sections above the V and restart those; then cut the main trunk to about 18" and let that one re-grow too.
Keep us posted!
