If not, you should budget between 10-12%. 

I budgeted $10,000 extra as a cushion on the rehab, and it seems as though others were simply hoping nothing unforeseen came up.

It also has a large pole barn on the property that I would still use for myself to run our food truck out of which is also why I would like to hang on to the property.

and how do we set a budget for this?

Was anything communicated during rehab when budgets were being exceeded?  

Specifically if a given property has updated systems and is held for a shorter period, the Cap Ex budgeted would be lower than a long-term hold with dated plumbing, electrical and requiring a new roof.Better to over estimate and have plenty of reserves just in case instead of the alternative.

You have a huge competitive advantage being a contractor since you can put some "sweat equity" into the deal if you wanted to save some money in the beginning, and you also probably are much better at estimating rehab budgets, getting great deals on materials, and keeping rehab timelines on track than the average newer investor.

I was swayed by the broader fundamentals in the market (pop. growth, jobs, etc.) coupled with the fact that I'm priced out of investing in Seattle.I'm hoping I've got the order of operations right here -- I figured I would start with lenders to see where I'd be in terms of budget by using the marketplace/Googling.

Are there roof repairs in the budget, again with a special assessment planned.

Lastly, a great agent will put your interest first, ahead of any possible transaction, and connect you with great professionals to help you with the purchase process (lender, lawyer, inspector, contractors, etc).The questions you should figure out before starting the search:- What is your budget?