Oh wow, inspired by the stunnel above I just successfully used

    $ ssh -Nf -L2049:my-nas:2049 my-gw
    $ sudo mount -t nfs -o vers=4 localhost:/mnt/somewhere/username /home

to mount my home (5,000 miles from where I currently sit) over ssh (over zerotier) without needing SSHFS. I'm going to use this going forward.