Just before the end of Topa Topa on the left is a gate that you may enter. That will lead you to the upper trails above Arroyo Verde or a better alternate route to the radio stations. However, today I hiked a different spot. At the end of TopaTopa, you can walk up the hill to the right and duck under the barb wire versus climbing the fence. The clouds in the sky above were amazing! Hiking up and to the left becomes nearly impossible, but you can hike to the right and it will take you all they way back down to Foothill. Some of the field portion is uprooted but it is crossable. This is a great place to just let your dogs run around. Nobody comes here! I would leave your kids at home. As you go lower, a canyon dip will separate you from the neighboring houses. Thus, the only real way to enter and exit this area is from the top and bottom. Check out the views on this day:
I took this picture on the next day at Balboa. The filed above on the hill is essentially what I climbed with the dogs. When I was done this day, instead of calling it quits, I leashed up the dogs and then walked down Skyline and then back up again. This doubled my mileage and elevation gain. From bottom to top along the hill, you may gain about 400 feet, but it feels like a thousand! The hill does go higher than the houses but with my old Dalmatian, I couldn't risk going thru the shrub already knowing that reaching the road to the Radio Stations would be impossible from this point. Better off going around to the side gate and hiking from that spot.