I am sure you have already done this but, my first step would be to look up the property on Zillow, Redfin and Realtor.com to get an estimate of the value.You want to get a thorough CMA or BPO to give you the as is value, the after repair value and the market rents.

Additionally, you're probably trying to be conservative in your estimates but why budget for a property manager?

If you want a rough estimate do the following: Count the number of beams that you think are affected and get the pricing for those joists, get the pricing for the joist hangers  and then replacement of drywall and electrical. 

I did start a spread sheet to track where I've sent letters, how much I've offered and pulled some data from Zillow and Redfine so when I do get a deal I can see how valid their estimates are.

I am thinking of getting a few estimates though as this current lender is charging a 3500 origination fee and haven’t seen the rate yet.

But you will get a lot out of it and there is a Volusia County meeting near you as well as many others and also several other meet ups..look for volusia repair estimates and some others on Facebook.Good luck.

I'm looking for a good way to estimate the value so I can make an appropriate offer, hoping to BRRR it. 

I’ve been looking at auction properties and ready to start placing bids but need a contractor to give accurate scope of work estimates.

Definitely leaning on good estimates during inspection and keeping in mind old houses will come with some surprises.Market is crazy right now, not much at all of this size in the city below 500K.  

Did you estimate low?