Income After Retirement

I recently began inspecting shopping centers as an independent contractor for a company that pays an hourly rate plus mileage (65.5 cents per mile) plus travel expense reimbursement ( hotel, meals) plus reimbursement for expenses related to specific properties (tools, ladders, etc.). Total payments from the company should not be in excess of $15,000 per year. My wife and I file jointly and our income consists of Social Security, pension and IRA disbursements. I’m concerned about how this new income stream will affect our tax situation and how best to account for this W-9 income. Will all of the money paid to me be included on the W-9 or just my hourly rate and if it is all payments, how do I go about subtracting the mileage and reimbursements from income on my return? 
I’m sure TurboTax will guide me through this process when preparing my return as it has for years but I want to be sure that I’m keeping proper records for documentation.

 

Thanks so much!!!