When determining ARV, do I just run comps for other 3BRs with similar condition, square footage, number of bathrooms, size of garage, etc?

The biggest mistake I made when I bought my first duplex (as an investment back in 2008) was that I did not understand the importance of square footage!

Know how to adjust each comp individually for bed bath discrepancies as well as living square footage differences.

I would measure your exterior square footage and multiply that by 3.5 -4 to get your total price.So 1,000 sq ft$1,250 - slate siding removal and disposalNew siding materials and house wrap $1,000 - $1,250Installation labor - $1,250 - $1,500This is probably on the cheaper end and it will depend on what type of vinyl siding that you go with.

Is it based upon square footage?

But I know a house just 2 streets over with the same bedrooms, bathrooms, and square footage that is a rental was just appraised for $65k a couple of weeks ago, so I think there is a good chance of getting close to that.

I've spent more on a house with half that square footage, so it's not unreasonable if that's what it needs and can be justified in the sale.  

@Brian NordmanIn this case, I would base the deduction of what % of the overall square footage is rented.  

.- Approximate sale price: $ 1 million- Approximately 60% of triplex is rented out (by square footage, as noted on our annual tax statements. 40% owner-occupied).- Current mortgage debt: $500k (we pulled cash out of a refi a few years ago to purchase/rehab another rental in Boise Idaho).Can we do this if we're buying raw land with intent to build?

Square footage & number of bedrooms dictate the cost a LOT.