If you drive to your vacation home, and don't do it frequently, and your media is stored on your home HTPC itself (not on an external server), I would suggest simply disconnecting the HTPC and taking the thing with you. No other method can guarantee the same user experience, quality and range of media availability.
JRiver Media Center does what you need too, but the quality will be limited by your upload speed from home.Not to mention that you may run into issues exceeding your bandwidth as well. Personally, I use my iPad/iPhone and AirVideo from home, but my upload speed precludes quality viewing. It's perfect for kids' shows though, and the most mobile solution. For 'proper' media experiencing, I often load up stuff I'm likely to want to see onto an external drive, and take it with me to play on a local media player device/laptop when I leave home. I have a couple of Patriot Box Office devices and a WD Live too.