Tight, but do-able. Do you have -

- Nexus card for entry into Canada + faster lane at security before US CBP?
- Global Entry for entry into the USA
- Checked bags to pick up / drop off?
- Status with AA

...?

All of those will speed things up.

When you arrive at the YVR international arrivals greeting hall, go up the escalators and turn right. You'll be at US Departures:

http://vancouver.citybytrain.com/wp-...-door-igns.jpg