Officially, the method is to perform a bootstrap recovery, which involves taking a bootstrap, shutting down Networker on your old system, then performing the process associated with the "mmrecov" command on the new system, which is not all that hard to do.
Unofficially, I didn't have any problems when I simply tarred up the /nsr directory on my old server and untarred it on my new server (7.2.1).
I will point out one thing in your plan I would *not* do, which is perform an upgrade and transfer at the same time. If I were you, I would either upgrade your old server to 7.2.1 and establish that it works as intended, then move, or downgrade your new server to 7.1.1, then make sure everything is working before doing the upgrade to 7.2.1.
I consider both of those to be major changes, and if something *does* go wrong, it's easier to track down what's broke if you only make one change at a time.