For vacant home, you may as if seller willing to do "lease with option to buy", so that your rent can become all or part of the downpayment and you can close in 6 to 12 months.
Unlike real estate agents who do much of there work on weekends, bank folk tend to disappear on weekends-just at the time you are ready to do something. Before you start to look get a pre-approval. There should be no charge for this letter and if you shop around and decide to use different financing-your credit union for example-getting the approval letter does not lock you in with any mortgage company. You need to find out a realistic price range BEFORE you start looking. If you settle for a house that you cannot feel comfortable in you will be calling an agent in a few years and paying a commission. In the market we had two-three years ago, you could make out selling a house after two years, I am not sure that this is now possible. On the other hand if you look at houses you cannot afford, the ones you can will not look so good. Get an agent using a co worker or friend's recomendation, then ask the agent to recommend a loan officer.
Your Agent will also be a great resource to you. Make sure that they have the experience to help you find different mortgage lenders that have special programs available to help you. Good Luck in your New Home!