I understand you wanting to "do" your numbers for your dealership and that sounds good BUT...

when the IRS come after you IF you hire an accountant you can blame HIM!  IF you ARE the accountant they'll just come after YOU!

   Well like I said, there will be a CPA looking at my numbers every quarter, and that would have to be done even if i did hire an accountant. They will be the ones doing all the IRS stuff. And all this is far in the future if it does ever happen, so who knows.

   And the reason I want to get my masters in accounting is also that I will have a career to fall back on if things down work out the way i want them to.

Equinetrans is correct about possibly being considered a commercial vehicle.  If you have any phone numbers or writing on the sides of your truck / trailer that can be easily read by people passing by, then some federal & state agencies could have probable cause & stop you under the rules governing commercial vehicles.  I am not referring to the tiny name / phone number of the dealership where you purchased your truck / trailer.  Also, not having your trailer tagged could cause some agencies to pull you over, especially if you are hauling from you home state into other states that have different requirements concerning the tagging of vehicles / trailers.  Also watch out for the number of pounds that your toe vehicle’s tag covers.  If that tag does not cover enough pounds to include both your truck & trailer, some one could pull you over & check it.

Here is some information concerning the use of advertising as a business expense from the US Master Tax Guide – 2005 – paragraph #969:

“Advertising Expenses – Advertising expenses are deductible if they are reasonable in amount & bear a reasonable relation to the business.  The expenses may be for the purpose of developing goodwill as well as gaining immediate sales.  The cost of advertising is deductible when paid or incurred, even though the advertising program extends over several years or is expected to result in benefits extending over a period of years (Rev. Rul 92-80).  The Tax Code and the IRS require that the cost of printing a catalog that is not replaced annually be amortized over the expected life of the catalog.  However, some courts have held to the contrary, taking the view that catalog costs are in the nature of an advertising expense.  The cost of public service or other impartial advertising, such as advertising designed to encourage the public to register & vote, are deductible.  The Tax Court has held that packaging design costs were a deductible advertising expense even though the design provided the company with significant future benefits (RJR Nabisco, 76 TCM 71, CCH Dec. 52,786(M) (Nonacq.)).  No deduction may be claimed for expenses of advertising in political programs or for admission to political fund-raising functions & similar events (Code Sec. 276).  This includes admission to any diner or program if any part of the proceeds of the event directly or indirectly inures to or for the use of a political party or a political candidate.”

 There is that... but the only time I wouldn't want to be called "commercial" would be going to horse shows/rodeos ( yes i do want to live vicariously through my children... nothing wrong with that right?), and it wouldn't be very business savy to not advertise then... so who knows.