Let me know what you think.1) The lots were going for mid 50's at one time - maybe more in the peak.2) Villages by me do not have a ton of duplex/4plex lots available.3) I was able to pick them up for 22.5k per lot (4 lots) and didit with 15% down as the bank also gave me the loan.

Other houses in the area are selling for mid 60's to low 80's.

@Parker Cox - although the link below is short and sweet, it provides a great summary of rental info across San Diego county for mid-year 2015.

It should go for mid 60's, and we offered 58,500 also; being worth about 80K currently.

If you look a bit further north in Montgomery County, there are nice townhomes for mid 300's.

If you're turning a commercial space into a duplex, I assume that's going to involve moving plumbing, moving electrical, moving HVAC, adding walls, building firewalls, etc.Assuming this is the case, so it's literally a full gut and reconfiguration, and if you're managing it yourself, I would guess you're looking at $60-80/sf for mid-level finishes. 

I see duplexes going for mid $60K but I don’t seem to find any comps.

BTW, my client just got an offer accepted for a SFR in Roseville (south of 80) 3 bed/1bath property built in the 50s clean, nice curb appeal with good roof and HVAC for mid 200s.

The costs that you listed for flooring, baths, kitchen, and exterior (including siding, windows, doors, and aluminum trim) match what I have been paying for mid-level finishes.

I have a credit score over 730, pay all credit cards off in full each month and make a pretty good salary for mid twenties.