Hey @Jeff Howard!
Happy Sunday!
I love that you are asking these questions. Sometimes folks just jump in without thoroughly investigating the area, other folks tend to be too nervous and never end up taking any action.
1) I don't think that there being that many houses in 1 area is a bad thing. Whenever the houses were built there had to be enough demand in the area to support it. And hopefully there is still that amount of demand. The question that I would ask is what is the vacancy rate of the area you are looking to invest in? If you knew how many houses were rented in that 1 square mile you could divide the number of empty units by the number of rented units. Let's say that there are 250 rented units (just a wild guess)... 14/250=.056 or 5.6%. That is a pretty low vacancy rate. This means that it would be wise to assume that 5.6% of the time your unit will be empty.
2) I do think it is wise to under estimate the amount of rent you can expect. It's always better to plan for the worst and hope for the best than the other way around. If you are new to rental prices in the area you are investing in, I'd suggest going to see other houses to determine how yours compares. If yours has additional features such as parking, storage, allows dogs, etc you might end up being able to charge more or the same amount.
We know our area pretty well, but when a owner wants to try to obtain a higher rent, we'll list it for them at their desired rate with the understanding that if we don't get any applications, we'll reduce the rent in $50 increments until we find a qualified tenant. It's always easier to reduce the price on your listing than to realize you listed it for too little.
And lastly, when qualifying tenants, it's always better to lose out on a few months worth of rent to find the right tenant than to jump at the first person who wants it even if they don't seem qualified.
Hopefully I've provided some assistance! : )
Ashley