The Shimano MD-P324 pedals work great for me because they’re flat on one side and clip-in on the other. I use my bike for fun and to commute to work, so having the ability to wear different shoes to ride in depending on what I’m doing next works really well for me.
Currently, one of my favorite MTB rides is Angel’s Staircase. It's a scenic high altitude ride that’s technical, challenging and long enough to keep me riding all day. Make sure to bring snacks and plenty of water to sustain you throughout the day. You might consider carrying a headlamp if you find yourself coming back to the trailhead in the late afternoon.