I like Mark Driscoll's approach to solitude -- get away, connect with Jesus in creation, and sometimes do nothing:
I schedule at least one day a month to get away and connect with Jesus. Because every minute of my day is normally scheduled, I don’t plan these days but just wake up and go wherever I end up. I do not answer my phone, do not meet with anyone, and usually get out of town. During a few hours of driving I do a lot of praying and sometimes worship God in song by myself. I like to drive until I am out of the city and find a small town or hidden secluded place in God’s creation. There, I do whatever I feel like. Sometimes I go for long walks and hikes alone to get fresh air, think, and pray. Sometimes I check into a bed and breakfast and take a nap and then go out to dinner. And sometimes I don’t do anything.