Not to the Trek event specifically, but if you want to get to Vegas from Canada the easiest way is to fly. Driving is cheaper but will take several days, and that's assuming you live in Lethbridge or Regina or Winnipeg - that is, close to the US border and on the prairies. If you're from further away, you'll spend more time.
(I'm guessing you're from Ontario, because in my experience those of us from everywhere else tend to remember that Canada is a big country and our experiences may well be different from those in other regions - but of course, this might also be my Alberta prejudices showing.
)
And "driving is cheaper" assumes you aren't losing money by not being at work. If you
are, then the cost of lost wages can quickly exceed the cost of airfare. Driving is also more of a hassle because you have to spend a lot of time navigating unfamiliar roads full of people who have different "unwritten rules" about how the road should work. Flying costs more, cabs or Uber at the other end all costs more, but it's simpler.
A couple years ago, flying from YEG to Vegas for a week cost a bit over 2 grand, airfare, cabs, hotel, and food all together. Airfare and hotel are the biggest parts of that, of course, but if one's not careful in the casinos and the shops that cost can easily skyrocket.
Still, to rough out a cost I'd start by looking at airfare and hotel costs, and then reckon on a minimum of 50$ a day for food, and then add a few hundred for the cost of entertainment. And for myself, I always add 15% to that total because I'm shite at sticking to the budget.
Good luck! In my personal opinion, visiting the States is going to be pretty risky for the next few years, but we all form our own judgements on that.
