My first Development Project. Any advise?

[Aaron Farr]

I purchased a brick rancher on 2.2 acres in a desirable part of Spokane, WA.  I'm in the process of getting the property subdivided.  It's been surveyed and so I'm about to submit everything to the county.  I had a preliminary meeting and it definitely qualifies for low-density housing and they didn't think there would be an issue with my plan.  Some details of my plan:

-Divide into 7 parcels.  One parcel will be the brick rancher which I will keep and sell at some point.  

-Paid 450K for the entire property and could easily sell the house for 350-400K even after it is parceled off.

-Build (6) duplexes on the other parcels giving me 12 units to rent.

-Duplexes will be one level ranchers 1200-1500 sq. ft per unit.

NEED ADVICE:  I'm considering making this a 55+ community.  It's in a great location for it and I am aware of other duplex communities like it that are completely filled with a waiting list.  They are getting $1800-2200 per unit!  

Is it a good idea to go this direction??  

Would you just go with standard stick built home or should I consider modular built homes?