It depends upon the bus you choose or if you're going by train - or both. The train to the Warehouse District is going to be about 36-38 minutes from the 28th Ave Station. The buses will differ in times, depending upon traffic. The 477 route (AV transit station, near the movie theater) will take about 30 minutes from downtown to the station. I don't know what the 460 would be like (transit station on Hgwy 13, near 35W) because you're on 35W most of the way and that stretch of road is a real b*tch. The 470 (Pilot Knob & 35E) is about the same as the 477. Lastly, of the routes I know anywhere near you, the 476, which goes to the Palomino Park & Ride (just south of Palomino Rd along Pennock Ave in AV) will save you a just a few minutes over the 477. It used to be a bigger difference, but that was before the Cedar Ave project through AV that just completed. You can check it all out with a better idea of times here:
www.mvta.com. It has a trip planner along the right-hand side of the screen.