Optimal number and location of branches

I need help in designing a framework/model to be used to determine the optimal number of branches for a bank. In particular; I require insights on factors that will be taken into consideration in this model Off the top of my head, I think the following internal variables/data will be useful; historical branch financials (like branch profitability, number of accounts opened, ATM card sold etc). Externally, here a few factors that may be considered (though not all may be readily available); Affluence, age brackets, density of population within x minutes of drive time, Density of competitors within x minutes of drive time, Location of current householders, Marketshare within region, Internal knowledge about frequency of trips by behaviour type and customer segment. Based on the above, the framework/model will be able to determine if a branch viable or should be trimmed. In making a final decision with respect to a freelancer, I would require a 2 - 5 page outline detailing the approach and variables and other considerations for the model/framework.