Parking is plentiful at Thunderbird Park. There are various parking lots for you to choose from depending on the trail you want to hike. Best part is that all of the lots are free! The trails are easy to moderate in levels of difficulty. There has not been a trail here that I thought was particularly challenging. All the trails are manageable whether walking at a relaxed pace or running them. I like that this park has so many options for trails, so you can easily go from one trail to another if they intersect.
It is really hot in the summer so most people go really early or late in the afternoon. Bring water. Beware of wildlife if hiking right at dawn or dusk. My dogs and I saw a coyote here -- exciting, yet scary experience.
Dogs are allowed here.