I have a client  that has been in the horse-show business for many years.  They bought a $225k motor home for the same purpose you are describing.  i used 25% as the business usage and survived an audit unscathed on that issue. I had asked my clients to create and maintain a website for  this business, which they did also.  but their volume of winnings/stud fees/etc were much more substantial.  I just set it up using a standard farm equipment useful life.  And the auditor was very pleased we didn't try to validate 100% use and therefore 100% deduction..