I'm more than a little envious. My own town has had some decent conventions over the years, but this is the big one. That, and, honestly, visiting Vegas in general is one of my bucket list destinations.
In terms of maybe asking questions at the panels, there's probably no question that they haven't heard a million times, but I do like to ask actors about roles they maybe don't get asked about so much. Everyone else asked Gates McFadden about Trek, but I asked her about doing one of the Muppet movies. Everyone asked Walter Koenig about Trek or Babylon 5, but I brought up "Moontrap", which was this low-budget sci-fi film that he made with Bruce Campbell in the 80's. I asked Robert Picardo about Gremlins 2 and he had a REALLY funny story. If I got the chance to meet George Takei, I'd love to ask him about working with John Wayne (he took some time off during season 2 of TOS to work with Wayne on a film called "The Green Berets").
Maybe consider getting an autograph from one of the lesser-known actors or crew. They probably don't get nearly as much attention and might actually appreciate it. Sometimes the object that you have for them to sign can be a conversation starter (such as a DVD for a non-Trek movie or show that they were in). I got Gerritt Graham (Quinn from Voyager) to sign a DVD set of "Gargoyles", for instance. Last fall, I got Garrett Wang to sign the magazine that comes with the Eaglemoss model of the USS Rhode Island, and I ended up being the one to tell him the company had gone bankrupt that summer.
I'm not sure how much time you have in town, but hopefully enough that you can experience a bit of Vegas itself. There's a lot to explore, like Fremont St, which is perhaps a bit more pedestrian-friendly than the Strip. (BTW, bring sunscreen and comfortable shoes!) I don't gamble, and I don't like the taste of alcohol, but, there are a couple of speakeasies, if you're into that. I'd love to try one of the high-end buffets, like the Wicked Spoon in the Cosmo or the Bachanal at Caesar's (apparently booking in advance is a good idea).
I've also heard that little things like snacks and drinks are cheaper the further you get from the Strip. Never buy a drink or souvenir at the hotel gift shop if there's a CVS or a Target nearby.
There's some really good Youtubers who have some good advice on what to do (or not do) if you're visiting Vegas.
JacobslifeinVegas is a really good one to look up.
Edited to add: Norma Geli has some suggestions for cheap eats, as well.
Enjoy yourself, and hopefully someday I'll be there to do the same!
