Hi judy,
You do not have to use Disney financing. If you can find a better interest rate such as a home equity loan, do it.
Most banks will not give you a loan with a timeshare as a collateral. Disney's financing will. If you want to go with a local bank, you will need to either get a personal loan (unsecured) or a home equity loan on your house.
Both the Disney loan and the home equity loan have real estate as collateral thus you may be able to dedut any interest paid on your IRS return. If you take an unsecured loan, the interest will not be deductible.