I’m gald you’re considering Tahoe! It’s so much fun! I think Mrs. DG would be the best to tell you all about the wonders of the north and west shore, but there’s tons of stuff to do in South Lake Tahoe, even if you’re not the most outdoor-sy.
Lake Tahoe is on the Nevada/California border, but the Nevada side of south shore is cheaper in a lot of ways. First of all, there are several big casinos you could stay at: Montbleu, Harvey’s, and Harrah’s all have room deals going right now. They also all have spas and pools, so you can schedule massages/pampering or just hang out by the pool all day. Next to the casinos is the Heavenly Village, which has a bunch of shops and restaurants and is great to walk around/people see. Plus, they have a gondola running in the summer (still going in September) which takes you up to hiking trails and another restaurant at the top of the mountain. And now you can zip line back down too (I haven’t done thie yet, but I REALLY want to!). To be right on the lake, I would recommend the Tahoe Beach & Ski Club which is in the Ski Run Marina, next to shops, restaurants, and the paddle boat launch.
One thing I always recommend to visitors to Tahoe is to take a boat ride around the lake. There’s several different boats (Tahoe Queen, MS Dixie II, etc…) but most of them take the same route across the south shore to Emarld Bay, circle the Tea Island, and come back. I personally don’t think the dinner cruises are worth the money, but sometimes you can find coupons in the local paper that make it a little more worthwile. I also recommend driving the Highway Loop around the Lake. It takes maybe half a day, but it’s considered one of the most scenic drives in America, and there are so many cute, fun stores and restaurants to stop at all along the way.
Also, there are a lot of cool historic sites up here to visit: The Thunderbird Lodge, Vikingsholm, and Valhalla/ The Pope Estates (where I was married!). These aren’t your traditional historical tours; most of the history up here is about illegal gambling rings, mob hideouts, etc… Also, Valhalla has a seasonal entertainment schedule that can be found on their website. They have plays, musicians, comedians, historic speakers, etc… and all of them perform in this boathouse with a back wall made out of windows so you can see the lake the whole time. It’s really beautiful! The casinos also have nightly performances of musicians, plays, shows, etc… Plus, they all have nightclubs, bars, jazz clubs, etc… that are open every single night of the week (and still pretty full every night in September).
If you enjoy gambling, South Lake Tahoe has the only non-smoking casino in Tahoe: Bill’s casino. Harrah’s has a new “fast” roulette game, too, that is partially computerized along with all the rest of the traditional table games. It’s pretty cool; I like it better than regular roulette. Plus, Harrah’s has daily poker tournaments. You don’t have to be good to join; my husband played once and he beat out several other people his first time!
For easy hikes/walks, you should check out Taylor Creek. They actually have installed a stream profile so you can look at the stream underwater; it’s cool! I also love trips up to Fallen Leaf Lake, which is only a couple miles away, but is always quieter/less packed with tourists. Angora Lake is also fun for a picnic or to escape tourist crowding at the popular beaches. It will be too cold to swim in the lakes, really, in September, but still warm enough to hang out the beaches or even rent a boat for the day.
If you have any other questions (like more activity or restaurant recs) you should ask! Plus, Mrs. DG will be able to help you out with all of the awesome things to do on the North and West shores. Tahoe would be an amazing spot for a honeymoon, but I might be a little biased.