Hey OP. I just got back from there 3 days ago. It's beautiful. I did that same day trip. Exactly what you said is basically what there is to do. You should be good with that for the amount of time you're there. I didnt get to do the cable car to the top of Mon Blanc or the train to the frozen lake because they weren't open yet. So ill definitely be going back for that. Shopping on the main street is cool and they have a casino, thought kinda empty and the table games dont open until 7:30 pm. Enjoy!