Since you can't enter into TurboTax that you both owned and rented, you will have to enter the lot rent as a Utility or Other Home Expense. I mentioned Utility because the rent may be considered for the hookup to the pad.
TurboTax will allocate it according to the square footage of the mobile home you entered. If you want to allocate it differently, you will have to answer Yes to the question "Do you have expenses that apply only to the home office". Then you can enter the amount of the rent you allocate to the home office.
