The Ultimate Parenting Plan must have sufficient detail to address every issue which could create an argument in the future.
Parents often choose to enter into a custodial plan with only generalities because it is easier than discussing and agreeing upon a lot of technical issues.
What Parents do not anticipate is that in the future, when those issues arise, (and they will in virtually every child custody situation), the parents are then forced to incur additional attorney's fees, court costs, frustration and anger when addressing the problem.
It is much easier to agree upon the details of a parenting plan before "the situation" arises.
When the issue is an abstract one, rather than one staring you in the face, agreements are much more easily obtained.
Also, you have plenty of time to resolve differences rather than trying to do so in an emergency situation.
Most Courts have some form of proposed custody orders or parenting plans.
I suggest that you ignore boilerplate forms.
Your family is unique and your custody orders and parenting plans should be tailored to your particular family's needs, not general forms used by thousands who go through the family court system.
Some of the More General Provisions in a good Parenting Plan include:

• Legal Custody: What decisions are made by which parent regarding health, education and welfare of the children.
  
• Physical Custody: Create a time sharing plan that is perfect for your family, not the boilerplate categories of a general form.
  If an infant is involved, you can include an increased time share plan.
  
• Summer, School Breaks, Holidays, and Special Occasions: Address each one of them, even your Birthdays, Religious holidays, weekend holidays, long breaks etc.
  to avoid problems in the future.
  

After completing the above, then turn to the less general, but equally important parts of a parenting plan.
A few examples are:

• What happens if a visitation is cancelled?
• Transportation issues,
• Child Care issues,
• Vacation and Travel issues,
• Extracurricular activity issues,
• Access to records, doctors, school personnel etc.
  
• Issues with religion.
  

Then there are the more esoteric issues which are equally as important.
Some examples are:

• No contact with certain people,
• Gun control,
• Smoking and substance abuse issues,
• Swimming pool restrictions
• What happens if a parent gets in legal trouble,
• What happens if a child gets into legal trouble,
• Relocation Issues.
  

The aforementioned are a short list of all of the issues which can and should be addressed in a child custody parenting plan.
During my 30 years of custody and divorce practice, I have seen and analyzed thousands of parenting plans and custody orders.
A good plan must contain plenty of options, however, it also must be easy to use and understand.
Some of the parenting plans I have seen lately would take an MBA months to figure out and complete.
Stay away from those that are too complicated or irrelevant for your situation.
Once you find the right parenting plan for you, take the time necessary to "hash out" differences in opinion with regard to every aspect of the plan so that when that situation arises in the future, both of you already have the guidance and direction to resolve the problem.
Often a custody coach or mediator is the fastest and least expensive method to obtain the help needed to resolve differences of opinion about options in a plan.
Try a coach or mediator if you and the other parent are unable to agree upon all of the terms of the Plan.
Put in the effort now to save money and anguish in the future.