DS, it depends on how much you have withheld from other sources, and the amount of tax you paid in 2016. You only have to pay in 90% of your current year tax liability, or 100% of last years tax liability (110% if you are high income) to avoid penalty. If you are covered from other sources make them wait until April 15th for your money, if not pay estimates. You might need State estimates too.
I'm assuming that your going to get a 1099-Misc for non-employee compensation. Report that income on Schedule C and you can apply any unreimbursed expenses against that (Mileage, Tools, Office Supplies, etc.). The net amount will be subject to the 15.3% Self-Employment tax(FICA & Medicare), plus Federal, State, and Local Income taxes but would not qualify you for unemployment. Hope this answers your question.
Ollie, it would not be hard to get back in. The industry is starving for good people.