What can count as duplicate expenses for travel?

[cas16]

I will be moving back in to live in my parents home and I will be paying for a couple utilities which comes to around 200$ a month. I am starting a travel nursing contract, so in the area I am in I will be quitting my job and picking up a 13 week contract several hours away, in which I will be renting an apartment at that contract location. After the 13 week contract I will come back home to my parents house for a month or two and then pick up another contract somewhere else. 

Where I am confused is if this will count as my permanent/tax home? I know I fit requirement 3 that it is my permanent residence and my mail will be going to that home and I will be staying there in between. Requirement 2 for a tax home is duplicating expenses and the IRS gives no indication as to what duplicating expenses means? Will just paying a few utilities count? Or will I have to pay my parents rent for a room at a fair market price? I hear that you have to pay rent or shared expenses at fair market price but I don't see where people are getting that from? Others say just utilities are fine, so its very confusing 

[ColeenD3]

Since none of your jobs are permanent and you are not actually moving to any of these locations, your parent's home is your tax home. There are many things that have to be taken into account when determining this, but in your case, it is by default. These rules are set up to determine what are travel expenses. If you are an employee, then these expenses are not deductible.

Generally, your tax home is the entire city or general area where your main place of business or work is located, regardless of where you maintain your family home. For example, you live with your family in Chicago but work in Milwaukee where you stay in a hotel and eat in restaurants. You return to Chicago every weekend. You may not deduct any of your travel, meals, or lodging in Milwaukee because that's your tax home. Your travel on weekends to your family home in Chicago isn't for your work, so these expenses are also not deductible. If you regularly work in more than one place, your tax home is the general area where your main place of business or work is located.

In determining your main place of business, take into account the length of time you normally need to spend at each location for business purposes, the degree of business activity in each area, and the relative significance of the financial return from each area. However, the most important consideration is the length of time you spend at each location.

Travel expenses