If you take Baseline Rd west to Central Ave, and head south, you get to the main entrance of South Mountain Park. Beautiful place with no entry fee. Nice ranger drove by me three times and asked once if I needed anything. Most fun work I've ever done. I took the main road in to Piedras Grandes. I downloaded the topographical map and found a good section that changed 100 feet in elevation pretty consistently and straight enough not to slow me too much.
The bike at Gold's Gym says I output 368 watts for 60 seconds.
The bike at a Scottsdale gym says I can output 520 watts.
According to the 20 foot contour intervals on that map, I can output 400 watts.
I'm disappointed, but it is better than being surprised when it counts.
I saw one other cyclist there.