Guinea pig questions

My 9 yr old daughter wanted a pet, she chose a guniea pig and adopted one from an animal shelter. Before we would allow her to she had to research about them and read and she did all of the above, she was very excited.

We got Truman when he was 2 months old. He was shy at first and would hide most of the day in his igloo, he has since gotten used to us and his surroundings and will come out of his igloo and "talk" to us and walk around in his cage. He is a little hyper though and will RUN and RUN and RUN. He has only been with us for about 5 weeks and is 3 months old now...we love him to death already.

He will charge at the person who is putting his food bowl back in the cage filled. He is NOT starving. He has pellets 24 hrs a day and water and then he gets fresh veggies/fruit 3 times a day.

We made him an outside pen that we take him to about once a day, depending on the weather and he loves it in there. My daughter sits in there and he is right up against her leg, she pets him and loves him so much. He eats grass and wanders around some but mostly is right up against her legs.

He does NOT like to be picked up though, which makes it hard to get him TO the outdoor area. He runs away from us in his cage. It takes us a while to actually get him to go out.

Today it took quite a while to get him, I was aggitated. I wanted him to go out so that she could clean his cage. I didnt want to wait for another day, I needed it cleaned today.

Any ideas how to get him to come to us more freely? Are we doing anything wrong? Do you have any ideas? We want to do what is best for him.
Thanks ahead of time!

Ohioan