I went to one of those USA/Canada Expo's a couple of years ago at the Southbank Convention & Exhibition Centre in BNE which I found disappointing as I thought there would be quite a few general information booths eg tourist bureaux, more hotel & tour wholesalers like some industry expos I've been to in the past.
Instead it seemed to be a massively overcrowded booking hall with FC Consultants from all their branches crammed in under the one roof doing bookings reminincent of a David Jones Boxing Day sale.
Save your time, effort & petrol money & stay home. I'll be you can find something cheaper yourself online as I'm sure there's plenty of people here on AFF willing to help you.
Are you flying ex BNE? If so what is your approx. departure date & what other stops to you want besides DEN? How many adults & kids? Any other plans eg skiing or must do's?