Hi, I'm hoping to get some help in figuring out what bike would be best for my daughter. She needs it for commuting into town during the summer to get to practice and to meet up with friends since she's not old enough to drive and her parents work. We out in rural area with rolling hills. Her uphill riding will typically be 2% to 5% grade. She will be riding on some gravel roads. She's 5'4" for now and is in the 90-100 lb range. The commute into town is 5 miles (to the high school) so I'm estimating that she'll be biking anywhere from 10 - 20 miles. Any suggestions?