FF,
This is the airline we used for Van to Terrace:
http://www.hawkair.com
I just punched in a rate for this Aug. 8th to 12th return Vancouver to Terrace and got $355 CDN. Almost half what you found.
I'd recommed San Antonio to fly to Vancouver, $535 (is that return?) is not a bad price at all. Honestly you will probably need a bit more than a grand to do this trip, but not much more. The plan would be to all arrive in Vancouver and all get on flight(s) the same day to Terrace where we will meet up and rent vehicles at the Terrace airport for the 4 hour drive north to Stewart/Hyder. Depending on how many of us go, we can go in a vehicle rentals/rooms and save. Also the rooms in Stewart are cheap - nothing fancy up there. Two in a room will be about $30-$40/nite. 3 nights/plus food.
We're still 16 months out. Plenty of time to save. I'm not sure how many will actually make it but the trip roster is huge. Nothing is carved in stone for this trip (even for me) but I am pretty sure at this point I will be able to make it. I plan to celebrate my 35th B-Day on Outpost #31 Ground Zero.
T