Most likely the state where the property is located is where lawsuits would be brought if they are something for personal injury like a trip and fall or something of that nature because the “cause of action” arose in that state.

But for individual lots to build just one home, you can use the methods above. 

Gas (natural or propane)I pay $100 a month for liability insurance.

If there's only a few comps you're using, there's naturally going to be a lot of error in your valuation model, so you're at greater risk of buying a home that really isn't going to net you much of anything. 

Is this a good approach or is there a more simple method of calculating an offer??

Find Brandon's videos on YouTube for the "four square" method of analyzing homes and practice.

You get tired after while if you follow traditional method.

My method to determine this is to do a manual comp analysis of properties on Airbnb and Furnished Finder.

This forum is mostly for the BRRRR method - how to rehab, calculating, stuff like that.  

Both of these may impact your DTI.One of the difficulties in holding properties for a long time is that equity builds up (either naturally or by forcing with renovation), and I need to sell or refinance to get the equity.