Substitute for mahogany/cypress?
For my first woodworking project I'd like to build The New Yankee Workshop's adirondack chairs to have some seating on the back patio. Norm used cypress the first time he made his adirondack chairs, mahogany the second time. I've been having trouble locating mahogany near me (Boise, ID).
I don't know much about sourcing wood for projects, so maybe I'm just looking in the wrong places. Boise Cascade and Weyerhauser have presences in town, but I suspect those are wholesale-only. Woodcraft, True Value, Lowe's, and Home Depot are all within 10 minutes of home. So as an aside to my main question, suggestions for places to find wood would be helpful.
Secondly, I get the impression mahogany is expensive and cypress harder and harder to find these days. What are the properties of these species that make them good for outdoor furniture (anything special besides basic rot-resistance?) and are there decent alternatives I might find in the northwest that are cheaper?