Private nodes has limited access from outer network for other nodes and SSH connection. So to connect you should to create SSH-tunnel to you node like so:
ssh -L 8545:remoteHost:8545 -N ethereum@remoteHost
Get it from github repo https://github.com/rumkin/ethereum-cloudconfig. Currently it has Ubuntu and x64 architechture support only. But I'm going to add more operation systems and test it on Hetzner, AWS and other cloud providers. It was checked on DigitalOcean only so any feedback would be welcome.
If you have scripts to start another currency nodes let me now and I will add them.