It seems like your plan will not work.
First, when you open an infopath form, the template must be either accessible or cached.
For the form template to be accessible, an internet connection and connection to the server must be present. To check what url the user needs access to, you can open the form that you are sending with notepad and find the "mso-infoPathSolution" node. Find the href field in that, that value is the url that must be accessible to the user. If it is behind a firewall, or a local address, they will not be able to access the template.
Another road block is if you have data connections. A copy of the data connections can only be cached if the form has been opened on that machine before. If the user will not have access to the data connections because of security, the same issue is present as the first issue.
If the user will have access to the data connections, you could send them the template (.xsn) file. They can create a new form off of the template, and the data connections will be cached.
Otherwise you may have to host your infopath on sharepoint and send them a link to the form from there. ([server]/_layouts/formserver.aspx?XsnLocation=[xsn template path])
Hope this helps, InfoPath is not very good at being sent places.