We are taking a trip with our two boys may 15th to 24th. They are ages 4 and 7. Neither has been in stroller for quite some time. I definitely want to rent one for the youngest cause I know his little legs will get tired. Should I just rent a single stroller or opt for the double so my older son ( who is small for his age) can ride when he needs to? Or should I just have them take turns?