I thought you said "Nothing to record at the county, I think" and the other part stated you weren't sure of the fees that would have to be paid. My mistake, I must have misread your answer.
Closing costs are typically the same as if you were selling a vehicle. Mobile homes are tracked by the DMV (department of motor vehicles) or something similar in your state. The costs are minimal, and it shouldn't be much of a hassle. Depending on your county, you may need a permit to put the home on your land, so it is best to let the county know to see what they do in fact require.
Good luck to you,