I've been to a half-dozen IFTD shows, including Salt Lake City (ugh), as both MFR and buyer. The joys of the show depends on what side of the booth you're on. I'd rather be a buyer than exhibitor any day. Set-up and tear-down is something I don't miss.
A show as big as this is hard to cover in 3 days, but you can do it. The average fly shop can only carry so many brands of float tubes and fly lines, not to mention the 'sundries' category.
The industry is driven by reps, not the FTD show. The MFRs rep is the real source for the average shop, and most of them are good at it. You learn what's going to be at the show from the sales rep, and you've probably seen most of it before you get to Denver. You have almost ceratinly discussed your pre-season order with them before the show. Yeah, it is nice to see Lefty, Dave and Joan, and to stand up there on the platform and show your stuff. When you get back, though, it will be your sals reps that keep you in touch with the industry. Most of them are pretty good gossips, too!

And you can keep Vegas. I liked Denver. Taking the long way home through Basalt is a lot nicer than counting your losses.