Excellent trip report! Some comments:

The HP club in LAS is not in a secure area so it's easy to exit security and hang out there... you don't have to re-enter security in the other terminal.

The Avis station in LAS is the friendliest anywhere and they are very generous with upgrades.

The Sahara buffet is notoriously bad. In fact, the days of good, cheap buffets in Vegas are pretty much over.

The Mirage interior decor remains one of the best in town.

There are TWO food courts in the Venetian. The one in the casino is MUCH better than the one upstairs in the Grand Canal Shops, especially the Italian deli at the very right.

You didn't mention it but I hope you saw the best free show in town: the dancing fountains of Bellagio!

Thanks again.