I'm sure others will have more information, but I know you will need an attorney, and you'll need to form a corporation to buy the place. That protects your personal assets should it not make it. Plus you'll need a business license from your town and county. An attorney will help you draft things and register with the state.
You'll also need to contact the former owner for their profit/loss statements to see how much the business made, which will give you an idea of how much it's worth. Does the business have a realtor selling it? You can ask him/her for a P&L statement. Is it in a strip mall or building where you'll have to pay rent, or is it free-standing and you will own the building? And payments on a business loan are made to the bank the same way a mortgage is -- monthly. You also will need an accountant to file taxes for you -- corporate and payroll and personal. I'm just spitting out things that are popping in my head.
You also should talk to your bank loan officer and see what the requirements are for getting a business loan. Usually you have to have a pretty detailed business plan (in addition to forming a personal corporation) drawn up to show how you plan to make a profit and not a loss in order to get a loan. Your local Small Business Administration can help you with drafting a business plan. You can also check some out online to see what they contain.
I don't know that a huge lot would be an asset. I don't know what your tax rates are out there, but a huge lot here always means huge property taxes.
I co-own a restaurant but I am mostly the silent partner. I do the bookkeeping and payroll and my partner does all the rest. It's a tough economy to open up a place, especially if it closed because it couldn't make it. Be very careful and seek out good legal counsel.