I think it is a good start. From my experience, people don't really know what they want -- they only think they do. An example of this is when Steve Jobs announced the iPad. There was collective confusion (more so than any other time Apple has done something). Now, we couldn't imagine our world without it.
That said, the participants of your survey will likely answer within their comfort zone or what they are familiar with. This is what they *think* they want. If you base your entire business model on what people think they want, you will end up duplicating what they are already accustom to (your competition).
Getting a sense of your market is a good thing, but you most have the "secret sauce" that will woo your potential customers away from their routine.
I don't know what type of restaurant you are aiming for, be it fast food, causal sit down, unique and interesting, or 5-star quality. Based on that, price becomes very subjective.
There is a very unique, one-off restaurant I enjoy visiting when I am traveling in Southern California. It is priced higher than any other restaurant in the area, but I am not paying for the food or even the service. I am paying for the way it makes me feel and the environment they maintain.
The participants of your survey will likely not be considering intangibles like this when they answer. Keep this in mind, but don't build your entire business around it.
Questions to validate your business model may include:
- How important is the selection of adult beverages?
- How important is the selection of healthy choices?
- How important is a family-friendly environment?
- How important is the quality of food (we don't always go where the food is best)
- How important is the speed of service?
Based on your question, I am guessing you are going for a family-friendly, speedy, inexpensive alternative to McDonalds, Burger King, or Carl Jr's. These companies have deep pockets to fend off upstarts. Your value proposition will need to be rock solid to defend against the giants of the industry.