I hiked 15 miles last Sunday up to the fire tower at Nordhoff Peak in Ojai. There is a 4300 foot elevation change. It was pretty sick and I could see the whole county. Here are two pictures I took. Ojai is a nice place to visit
45 minutes straight maybe. (I'm a mix of Forrest Gump and Chuck Norris). Any good amount of running is good. No matte what your size or age.
When I was in shape last year I used to run 3 miles each day so I was able to run 30 mins without any problems.