This was hair-ripping time! I looked everywhere and all I could find was a cifs mount for directories that are already on samba. My directory was to be shared over samba. I hate it when Linux decides it knows best.
For Debian, I finally found that there is an if-up.d directory in /etc/network. This sucker is only invoked after the network is up, and if you have network-manager, it comes up very late indeed.
So, nano a file, I called 'aftermount'. Here it is.
#mount after network up
mount /dev/sdb1 /disk4
I put a religious empty line at the end. This is run after the network. After you create file, you have to run 'invoke-rc.d aftermount start >/dev/null', everything while root, or do the sudo thing. Also chmod a+x aftermount to make it executable.
Then the stupid thing works. (I write these things for myself in a year).