I am new to Turnkey, but found the installation very easy.
I am using a static IP and can get to the Webadmin screen via Https with no problems.
Should the sample Ruby on Rails app fire up automatically or am I missing a step?
The Passanger module is a new thing for me as well so perhaps I missed something there.
From the description it looks like Mongrel was dropped so the script/server command is not going to help.