Talk with Tritonman, Happykamper or WAWI on here. They know their stuff. T-man started from a trailer on the side of the road and moved to a building within two years. Quality product was the key.
We just got our final permit from the Fire Marshall yesterday to finally start work on our new location.
As for advice, I'd say follow your dream, but don't mortgage your future. I started out in a food trailer with 5 picnic tables 2 years ago. I did not grow the business unless we could afford it, and still remain debt free today. We only grow when the business dictates, and when we can afford it. Our new place will be 4,000 sq ft, plus outdoor seating, and will be about 80% paid for when we open.
Is it an azz whipping? Some days it really is, but you just keep doing what you love, and it'll work itself out. I'm scared to death of opening this new place, but you have to put a lot of trust into the guy upstairs. The business will tell you what it wants.