102 inches is legal, but that must include your side mirrors too. Wide body motorhomes have the body being 102 inches and the mirrors can stick out at least another foot on each side. How far you can stray from the interstate varies by state.
Sometimes, you need to know exactly how many years, months and days between two dates, in this situation, the following long formula may help you. 1. Years,  & DATEDIF(B1,B2,YM) &  Months,  & DATEDIF(B1,B2,MD) &  Days. Note: In the above formula, B1 indicates the start date and B2 stands for the end date, you can modify them as you need.
To count how many weeks between two dates, you can use the below handy formula, just subtract start date from the end date and divide by 7: 1. Enter this formula =(B2-B1)/7 into a blank cell, (B2 indicates the end date and B1 is the start date), see screenshot: