Problem #1 - most homes with in-law apartments are not small. We also do not have a lot of formal in-law apartments in the Springfield area. You are best to try and find a home that might suit an in-law arrangement.
In order to determine what might work for you - we would need a lot of additional information (i.e. price range, rooms needed, and other wants and needs). You should do some preliminary searching to see what you are looking for so you can be as specific as possible. You also need to talk to a local lender to ensure that you are aware of what you are qualified to borrow.
Brian P. Sears
I would post another question looking for a Realtor in Springfield Massachusetts.