Rockwork wall at back of play area for Dragons, themed stands behind Sky Fly rides, and berms at the back of Dragon coaster load/first launch... I don't think you'll be able to see the hub coaster from within Dragons, but the view from the back half of the hub coaster will be interesting. Probably a lot like Dueling Dragons, where you get a view of backstage stuff, parking lot, etc.
EDIT: The dragons coaster literally goes into tunnels beneath the rockwork and the stands at the back of the land, so you wont be able to see outside of dragons from the second half of the dragon coaster where it gets closest to the hub coaster for sure!