You are not even saving enough to pay for 1 item in a capex budget.

Location and cost were the initial items that appealed to me.

See if you can find any owner finance deals.Even if they will only carry back a 2nd mortgage fornthe downpayment on traditional financing. 

While some companies already offer this using traditional systems, it is limited to upscale vacation homes.

I would look outside the traditional areas where most investors look in GR (Downtown, Kentwood, Wyoming, the Lakeshore) and start buying in more rural areas that are just a little too far out for most investors. 

Whether it be a primary residence or investment property, 25% down is the bare minimum for a traditional conventional loan.

In a traditional Real Estate market adding to a property will not increase the value enough in the short run to cover the cost of the improvement.

These can be high ticket items so look beyond the pretty counter tops and new flooring ( in my opinion).

I realize the appeal of a traditional duplex but there are other options and ways to approach the situation if you're interested.Hope this helps! 

Next item to consider is the lateral system.