Alright, did a little digging, and some testing, and found this:
http://www.arches.uga.edu/~pkeck/ssh/
Summary
Use ssh-keygen to generate public & private keys
copy key to remote host (via scp)
start up ssh-agent
use ssh-add to add those keyfiles to the agent
scp/ssh/sftp freely.
This is roughly what I did on my machine(s)
It seems to work just fine from the command line (scp works without password prompt), so it should be good for a CRON job.