Hello @LLcoolAid and welcome to Phoenix! You definitely have some options. One question- are you looking for hiking, trail running, biking, or a combo of these activities?
As to long flat trails, some of my favorites are: "Desert Classic" at south mountain. It's a nice meandering out and back trail so you can go short, or do the whole 17. 5 miles with only about 800 feet of elevation gain (there are some short ups and downs as you cross sandy washes). The only downside to this trail is that it can be busy and it gets a lot of mountain bike traffic- so you'll definitely want to keep music off so you can hear folks approaching.
Another favorite, but a bit of a drive, is "Pemberton Loop" at McDowell mountains. It's a 15.4 mile loop with only 880 feet of elevation. This one will feel nice and remote and have great views of Four Peaks too. There is an entry fee to get in (currently $7), but its much less crowded than South Mountain and can be worth the drive.
Lastly, I'd recommend Usery Mountain Regional Park. Another great option with very cheap parking and if you stick to the lower wash trails south of the mountain you can run loops (Belvins or Spillway) and these barely even have 100 feet of elevation between them.
Check our our free apps called "Hiking Project" or "Mountain Bike Project" if you'd like to see metrics, photos, and real-time trail conditions from current users. Here's a link to get you started Mountain Bike Project
Let me know if you have more questions specific to a certain activity. Have fun, stay hydrated, and don't forget social distancing practices.
Best,
Jim
At REI, we believe time outside is fundamental to a life well lived.
