There's definitely still stuff to do in North Lake, but most of the bars/restaurants close at a decent hour. There are some casinos on the North Shore, the CBC and the Tahoe Biltmore right across the stateline, but they're nowhere near as classy as the South Lake casinos, but you still get to gamble and get free drinks.
If you're looking to get rowdy at night, or just have more options, definitely look into South Lake. Granted, if you stayed in Truckee, Reno is only a quick 30-40 minute drive.
Northstar and Squaw would be the two main resorts I would hit. Both villages have an extensive list of restaurants and shops, so the girlie can keep busy during the day if she decides not to ride. Heavenly/downtown South Lake also has a great scene for someone not really interested in riding.
Kinda just depends on what you're looking for/to do.
What do you count as a "decent hour"? And you mentioned hotels.com, you strictly talking about S. Lake Tahoe? Considering I grew up in Vegas (after the aforementioned birth in Reno) and my gf doesn't gamble I have no wish to spend time at a second rate Vegas. If we want Vegas, we'll just go there. I would like a few chill bars, and activities to do. I'll probably take a day off of boarding to hang out with her. So is there some shit to do?