I'll soon be contracting back to the company I retired from via a general contracting company. The general contractor provides various services to my old company so I'll join this contractor company as an employee in order to work at the job site for my old company. I'll use my RV as my temporary residence while in the area which is about 400 miles from my permanent resisdence. I'll drive from my temporary residence to the job site daily four times a week and will travel to my permanent residence every 2-4 weeks.
So, for tax considerations, are any of my temporary living or job expenses deductible (mileage, RV site rental, RV electric, etc.)? If not, is there a way to set myself up so they would be (e.g. S corp, sole proprietorship, etc.)? This job will be a one-time effort. After it's done I plan on staying in retirement permanently.

If your contract work is less than one year in length, then you CAN deduct your daily living costs on the contracting job because the job is considered to be temporary in nature.