J.S.
Well, according to your zip code for spring valley, you look like you are kind of in a newer area of spring valley.
There is a park off w. flamingo and torrey pines.
(near busy street)
There is also desert breeze park off spring mt and durango
(little large, not to many trees)
Then there is Paul Meyer Park. (Older park, well kept, last time I seen it) it is in spring valley sub division off buffalo and trop, (look on mapquest.com) it is right behind a elem. school. (it is fenced off from the school, so it is opened durning school hours too.. quite little area away from busy traffic. Nice little place for picnic and playground with trees.
Also look under www.co.clark.nv.us
under the tab marked department P and click on park and recreations.
good luck