We are really blessed to be in a troop with 10 ASMs and a lot of supportive parents. Even when boys turn 18, some of them and their parents choose to remain active. When one ASM was asked why he still did scouting although his boy was over 18, he told the questioner, "People my age don't like to go backpacking and hiking, if I work with the boys, they'll let me go with them on weekends."
Our troop has sign up sheets for every outing. There is a due date on them. They used to be mailed to us monthly but are now sent via email. If you don't receive one, there are copies at the meetings. Each one states the dates and times to leave and return, how food is being handled, fees, and whom to contact if you have any questions. My son had to pay a $5 late fee the first time his paperwork was late. He's been much better about making sure it is ready to go since then.
We also have parent meetings monthly while the scouts are meeting. Each agenda includes what has happened in the last month, how it went, parent reactions, what will be coming up in the immediate future, and plans that are still a ways out. A printed agenda/report makes it easy to remember what is happening and when. The SM can come in if he needs to speak to us, and it is a convenient way to address as many parents as possible at one time.
This troop has been around for 18 years -- the SM is the only one the troop has had -- so they have had an opportunity to see what works best for them. The communication in the troop is excellent. Our family can plan around our son's scout commitments several months in advance.
Hope this is of some help.