A bed and Breakfast is a commercial property. However, depending on your state statutes and regulations, residential appraisers in certain states may appraise commercial properties up to a certain transaction amount in some states there is no such limitation for non-federally related transactions. Other states limit residential appraisers just to residential properties federal transaction or not.
Having said that, there are many differences between an appraisal of a residence and that of a b&b. If you are allowed to proceed, do so l=knowing there is a quite a bit to learn about.