Migrating to WP – Correct prosedure?

Hi – Hope this is the right forum
I’m planning to migrate our site (www.dolcevita.no)from simple html pages into a WordPress based CMS (using the Remix theme) – and I’m hoping for some thoughts on how to do this, to make the visible part of the “switch” (downtime) as brief as possible.

Would this be the best way:

• Install WP in its own (wp) folder on the site root
• Copy all contents into new pages and posts in the for now “invisible” wp part of the site.
• Once everything is ready, move the index.php to the root (using the appropriate procedure for that) to activate/ make the new wp site visible (and of course remove the index.html and other html site files).

I’ve used WP for about a year for our blog and forum, so I know a bit about how things work.
Am I basically thinking right? Any fallpits I should be aware of?

Thanks,
Kjetil Flekkoy