Set up template on the site offline and then create a packag

I have a site at the moment - http://v-boge.org (J!3 with (M)Social at the moment). I wanna put the Quark on it. But the thing is that to really take the full benefit of Quark, it'll take lots of time to study howto's, come up with good use of those on particular site and actually apply 'em.
I don't know how to do that on live site without hurting it or switching templates prematurely (would be thankful for advice if there any). I know how to backup the site and roll it out on localhost, so I can do all that locally. but since I can't just do only that - it'll take few days or even couple weeks. During that time people will be coming to the site, adding stuff, comments, reviews and so on. So setting everything locally and then just restoring it on live one won't work, because I'll lose some content.
So, I was thinking, the way you create QuickStarts for your templates could help - if I do everything locally, convert it into MY QuickStart and then install on live site without installing content - it should work. But how do I create QuickStart? Could you, please, teach us how to do it???
Thanks.
PS. Or may be there's any other way to do this?

Actually quickstart contains entire database backup + all modules required. So it doesn't differ much from normal backup of files and database + installation interface.
If I would need to do so change, I would develop it locally, saved all template and modules settings I have made, and then restore them manually on live site. Or just made a 100% backup of the site, turned it offline, made changes locally when I would already knew what to change and then bring the locally version back online.

Is there a way to bind modules to templates? Like when I switch templates now, I have to manually turn off all modules created for (M)Social's frontpage and turn on all that are created for Quark's frontpage. Maybe there is a way to automate it?

I'm not quite sure. All that comes to my mind is to use sql queries but this is way beyond simplicity of Joomla usage .