You could take a look at https://github.com/x-team/wp-cli-ssh
Seamlessly run WP-CLI commands on a remote server via SSH
I know you don't want to SSH to the guest, but this at least, supposedly, removes the need to do it manually.
Some instructions here: http://x-team.com/2013/12/optimize-your-vagrant-workflow-with-wp-cli-ssh/
Although I couldn't get it to work since I can't figure out what version constraint it is asking for..