You can find it in the upper right of the main viewing pane (not the top bar). Pardon the techincal non-technical explaination of where it is. I could have just said click the linkylink on the doohickey thingimigummy.
I remember playing 25th Anniversary at a Star Trek Convention in the early 90s.
Depending on where you live, most old (in years) GOG games are the price of a froofy coffee beverage when on sale.
Hopefully more Interplay published Trek games will come out on GOG. Holding out hope that Starfleet Command 1, 2 and OP will be included. I've long since lost my install media for them and would love to replay them.
I've always been a spoiler-hound. The more excited I am about a thing, the more I want to be spolied; even if some of the spoilers are dead wrong. I also like (when possible) to read the novel of the movie before the movie's release - even if it ends up a disappointment to NOT see a favorite scene in the book in the movie.
If you have the time, you owe it to yourself to hit up Hoover Dam. It's not far out of Vegas, and easily doable on a day trip. The Grand Canyon is also somewhat nearby; take a couple days and head out there as well.