Is she on the title to the manufactured home? If not... and you didn't agree for her to pay rent or that in return for the loan she could stay in the trailer as a term of the loan, she's got no right to use the loan as grounds to live there.
If all she did was loan you the money for the downpayment and she's not listed on the title of the home, all she's "entitled" to is having her loan repaid. That's all you promised her at the time. My bank loaned me over $100k for my house. They have a mortgage on it. That doesn't mean that the bank's President can show up to my door and insist on bunking with me. Same thing applies to ex-wives who have no legal title to the house.
In other news, you could give her a choice: either credit what you've been paying for her share of the utilities etc towards her loan and for as long as she lives there or she moves out by the end of the month. If she doesn't agree, give her a three-day notice to leave the premises. On day four, go to the local municipal court or county court that has jurisdiction over where your house is located, and look into filing an eviction action against her.
She may sue you for nonpayment of the loan, but since she doesn't have a mortgage on the property, she cannot foreclose on you. (Tthe primary lender already has a mortgage on your property that would be first in priority and I doubt there's any real equity in the house. for her to collect on.)