What hardware to buy for multiple rooms?

I have an HTPC in the living room running Windows 7. It’s great! I use Kodi to watch movies and tv on the hard drive. I use WMC to PVR OTA content. (I originally set up ServerWMC to integrate with XBMC, but had trouble getting it to work with the newer Kodi updates and gave up.) I use a SMK‑Link Utlra Mini Wireless Keyboard as my remote (VP6364)

I just got a TV for the bedroom and I’d like to watch the shows on my HTPC from the bedroom and have them marked as “watched.”. I’d like to be able to use a duplicate SMK-Link remote so that my wife doesn’t have to learn new things. What is the cheapest, simplest way to make this happen? What should I buy? Raspberry Pi? WeTek Core? Chromecast? Something else?