Ideally parents will agree on how to share the summer recess time with their children even if they are in the middle of a contested divorce. However, experience shows that sometimes lawyers have to negotiate or have an attorney for the child appointed or arrange for a custody case worker to assist.
While most parents do not divide the summer equally in half, that of course can be done. Instead most parents arrange to each have two or three weeks of exclusive parenting time with their children during which the regular school year parenting schedule is suspended. This way each parent can go away with the children without the daily/weekly back and forth of the "regular" schedule. Some parents will provide that the week not be consecutive whereas others do not object.
The first step to working out the summer schedule is communication with the other parent. Ideally, let the other parent know which weeks you want by May 15th, this way the other parent can also make plans for the children. Sometimes, the parents will have a "stay cation" where they do not travel but stay home and do local activities or just hang out with each other. The key is to work it out and to consider what are the usual summer plans for the child and whether the parent's schedules can take that into consideration.
If a child goes to camp will the parents' time be limited to the weeks before and after camp starts? Should the child go to camp for only 4 weeks instead of 8 weeks? Are there other concessions that can be worked out using other school recesses if necessary to adjust for less summer time due to the child's activities?
Parents that truly desire resolution will reach an agreement. Parents that cannot be flexible or where one parent is unreasonable will be bound for court.