I don't generally recommend creating the site content on your dev machine then moving it to hosting because it is more work to do it that way and requires making a backup of the database and restoring it at the host. I find it much easier to just install it and create the content at the hosted installation. If you want to keep it private until launch time you can close the site from Administration and then the pages and content can only be seen when logged in as admin.

As Joe Davis mentioned you don't need the source code unless you are developing custom features to extend mojoPortal and you certainly don't need visual studio to create content. Our download packages don't even contain any c# source code, they are pre-compiled. People often open the pre-compiled deployment files in Visual Studio and then think they have the source code but they do not. You may want to look at the article Understanding the Difference Between Deployment Packages and Source Code. The VS publish feature is used for making pre-compiled deployment packages  from the actual source code which could then be deployed to hosting but we do that for you when we make official release packages. Opening our pre-compiled package in VS and then publishing it is pretty much pointless since it is already compiled and has no c# source code. 

Hope that helps,

Joe