I'd look into the HTPC (home theater PC) community. Many of your problems have already been addressed. "htpc keyboard" on Amazon pulls of plenty of options for you to consider
E: If you've got the money to spend, there's no reason to do something as unsightly as external HDDs>laptop>>HDMI>monitor when Plex exists and is plug-and-play. Throw your laptop and drives in a closet or a backroom and put a Roku (or Shield) on the "TV." Much neater and you can navigate with the remote too.