Two homes on a single lot - what gotchas should I be aware of?

[Jason Lucas]

Hello,

I'm a first time landlord.  I'm looking at a property that has 2 homes located on it. The description states: "it is a Invest type of property with 2 houses on one parcel that CANNOT be separated per the city". Both homes were built in 1943 to give an idea of age. 

1. How does landlord insurance work for this since there are multiple houses? 

2. What's the best method to calculate expenses as there would be 2 homes to maintain? Just double everything in the estimating calculator?

3. Are properties like this typically hard to sell?  Since this is my first one I'd like to be able to trade up after a few years. (currently has been on the market for 44 days with one failed attempt to purchase)

Any other advise?  Thanks in advance.

Jason