They come into the basement and cut out the concrete slab about 2 feet from the exterior wall continuously.

I am also from the Inland Empire and getting my feet wet as Real Estate Investor.

If a lender hires an appraiser to appraise this house, he/she will certainly get it done...they can't just report back, "sorry, I couldn't find any comps".An appraiser usually starts with homes of similar size/age/construction/square footage within a half mile, and sold within the last six months.

Put in your parameters like bedrooms, square feet, subdivision, etc. 

I do a lot of business out in Worcester which is fairly close to you, that is a huge market and even though the final sale prices are lower out there than Boston there is just so much business to go around, which might be a good place for you to start getting your feet wet if you decide to get into sales(not rentals) .

A previous owner did the addition before records were kept, and it is included in the square footage of the house, according to the assessors current records.

There is a big difference between renting a one bedroom with its own kitchen, bath, living room etc that is 800 sqft And a 3 bedroom that has shared facilities and 1400 square feet.

(Buying a square block in "just the right place" in Detroit 4-5 years ago for example.)I'd look at bestplaces.net see the outlook and true stats for the area and gather as much other relevant data that could be used to reach your goals.

Depending on the total square footage of the residential vs commercial space, you will be between a full commercial lender or a wholesale investment lender that can dabble in the mixed-use space.

Stats on the house:Approximately 2400 square ft.1st floor -            - two full bathrooms, 1 large living room (14x16), 1 small living room (10x12), and kitchen(10x12)2nd floor            - One large bedroom (14x16)            - Two smaller bedrooms upstairs, but you have to walk through one bedroom to get to the other.Comps in the area range from 220k - 300k.Rentals Comps would be 1700 - 2200.The front of the house seems like it would be "picturesque" for small venue events.