Perfect, effectively the problem with Ghost not being forwarded was that the address use by Node to listen is, by default, 127.0.0.1
A quick edit in the config.js file to replace the Production settings with 0.0.0.0 instead did the trick, and now Ghost is running in my Vagrant instance, and accessible from my laptop browser, and it looks good.
Making a post is very simple (I have been using markdown for a year now, to write anything I need formatted). There are no funny questions, nothing strange. Ghost seems to have a very low barrier to entry.
Tomorrow I will look on how to edit the theme, and to load my content generated with WordPress.