This will get you a lot closer to an accurate number before you have drawings. 

I'm also entertaining the idea of staying put and just taking out a big HELOC, but my fear of getting stuck in this house and town is significant.....I don't gamble at all, and I don't watch sports.

When the legal documents for a deal arrive, make sure the legal paperwork is complete and accurate.

Also what is a good way to accurately calculate expenses on a small multi-family.

Having an excellent bartender staff that makes great drinks consistently is key and does accurate pours.

As Gareth said, learning how to run the numbers accurately is also of utmost importance, especially when it comes to marketing the property to your buyers -- they will not go for the deal if the spread is not wide enough.I wrote a few biggerpockets posts on how to run comps, estimate rehab costs, and find motivated sellers and off-market properties, they are all here: https://www.biggerpockets.com/blogs/8814-investing-with-rei-kitI feel that the most important information is how to run comps, as without that you are at the mercy of what the seller says their house is worth and have no baseline for where to start negotiations: https://www.biggerpockets.com/blogs/8814/68395-how-to-find-real-estate-comps-and-calculate-after-repair-valueYou should start creating a buyers list right away, as getting a property under contract and running out of time to find a buyer is a real possibility.

I know it isn’t 100% accurate, but I’m able to enter the address and then check current available rentals as well as see estimates.

In my opinion, the private flood options rate maps are more accurate at assessing the “true risk” and associating a premium with it.That being said if your property is in an X-flood zone (those not required by lenders to have flood insurance) then the government policy (which is subsidized) is a no-brainer you get great coverage at a low cost. 

@Henry Lazerow has pulled some visually accurate comps with similar rent rolls.Figure out how to pull out the most amount of cash to throw into the next deal.HELOC: My lender has a 95% LTV HELOC at prime +1 with a 5 year draw period and 10 year repayment period.Cash out refiOnce the appraisal comes back and hopefully with more research I can figure out the most optimal next steps.

The most common and perhaps most accurate is the income approach.