Glad to see you are accessing some of the resources out there! I've found the easiest way to project rental income is to take a look at other local listings in your area. I like to search online because it is easy to access and totally free. In our area craigslist is the place that everyone finds rentals, but in your local it might be a different online resource. Just type, your location and then rentals in a google search box and some listing sources should show right up. It'll give you an idea of comparable properties and what they are listed for rent at. Keep in mind that just because it's listed at a certain price doesn't mean they will get that.
Also, the condition and location of the property can be a factor when comparing rental prices.
That's inline to what I was thinking. I wasn't sure if there are tools out there that calculates by the criteria and spits out the estimated rent amount (wishful thinking haha).
I've heard of Craig's List as the source from another of my investor friend in NJ area.
We have a private leasing section on har.com but I will check out Craig's list as well.