We have been very fortunate with ours. We bought two homes on one lot for $155,000, living in one and renting the other. Our effective "rent" (our share of the monthly nut after rental income and expenses) has been under $400 a month. We renovated the rental about ten years ago (using refi money) got new tenants at higher rent, and the appraisal for our latest refi came in at over a half million. The new tenants have become like family. Like I said, very fortunate!
And you live right next door. Makes a big difference or at least it can.
Best of luck to you.