What kind of farming are you doing, or do you intend to do, if you are running dual vocations?   That will dictate the flexibility you will need in your off farm job. 

Regarding the law vs MBA decision, sounds like you would prefer to go the MBA route.  You indicated you like numbers so you might want to consider going with a Masters in Accounting.  You also need to research the job market in your area and see what might be in demand in a couple of years. 

From what I have read the legal profession and MBA degrees are pretty competitive job wise at this time.  

Going back to the accounting side you could possibly work for a local accounting firm and get your CPA.  That would allow you to stay with the firm, go into industry or set up a private practice.  

Most of all, go with what you enjoy.  Money should be a secondary consideration.