I walk our dog every day. During the week the walk starts after my kids get on the bus. On the weekend the walk is a family walk after breakfast.
We use the black tie handle bags from Target. Tie handles work well for smaller hands....since my kids can't tie knots yet.
If I pass a park I'll toss the bag in the trash there if she does another poop....or carry it back home.
Usually our dog goes out at 6:30am with me and poops right away. I pick it up and leave it by our side garage door. It doesn't really smell in those bags. Whenever I bring out a bag of trash from the kitchen I pick up any doggie poo bags and toss them in before I put the trash in the outdoor trash can.