I would not trust that time estimate to Sevierville, especially on a weekend. It could easily take you double or triple the time, unless the hotel is directly off I40. Another option to look at would be a hotel near a community rec center. Here in Georgetown we have the usual interstate chain hotels, and about a half mile down the road we have the Pavilion which has a full sized swimming pool, waterslides, and a kiddie spray area, along with basketball courts, a walking track, weights, etc. Cost of admission is $5 a person.