You and the seller can negotiate the financing terms and come to an agreement. Also you may want to talk to the mobile home park to find out if the seller is up to date on any lot rental payments, plus find out if the park has any restrictions on mobile homeowners selling their units in their park. While you do that be sure to ask about park rules and find out what if any utilities are included in the monthly lot rent. It may be best to discuss your intention with an attorney prior to entering into an agreement with the seller to protect your interests.
All the best,