Have you spoken to any of the "customers" who would be in the target market of your app?
Are there existing competitors? (If so, much of the market definition and research is a lot easier)
Get a mockup done (just the UI with no functionality). This will be essential for you, for the potential users and for talking to investors.
How about posting a Request for Proposal to any developers you know, or to networks that might be able to help you. Based on the numbers people get back to you, you can tell if what you're trying to build is really simple from a technical perspective, or really complex, and potentially not possible.
Alternatively, reach out to your network asking for referrals for developers who might be interested in joining as a partner. That way, you'll have the technical expertise as part of your founder team, which, considering your business is being constructed around a technical product, is probably a good idea in any case.
What capabilities does your app need that you are not sure can be developed? The current technology should be able to meet any data entry needs. Unless you need extremely high-end graphics, massive amounts of number crunching, or a hand-held retina scanner.
One area that can be tough is if you need to integrate with other applications and your customer's local computer network (Many companies have not bought into the SAAS and cloud strategies.). It can be done, but you may find yourself having to do too much customization unless you offer an API and let users build their own integration.
We could be more helpful if we new what your needs were.
I would suggest a service like www.biznessapps.com/how-it-works.html where you can develop and even resell your app ideas without any programming experience. This can help you see if your ideas have "legs" or if they need more refinement. It is a minimal risk (monthly subscription fee) with a good ROI.
You are totally on the right track developing for a local market. As Google moves more and more towards personalized, local search results, local app developers are having much success; especially for basic services, such as restaurants, theaters, gas prices, you name it.