I think the easiest is to have an llc in a state with low filing fees and lax record keeping requirements which would be Wyoming or New Mexico. LLC are just treated as pass through for tax purposes and c corp are by default taxed as corporations but can be elected to be pass through like an llc. The tax doesn’t matter as even if the Corp were to generate a net income I could just pay myself a small salary for managing it. This is not the first business I have owned so i didn’t need to be told by the other poster that LLCs and s corps are not free
Based on your questions and your sophistication, I think that your bigger issue is how strong the corporate veil is between business activity and personal activity under the various options. That's a legal question, that you should ask of an attorney who is savvy and skilled in that area of law. Personally, I would expect to pay a minimum of $500/hour for that type of advice. So, getting even minimal decent guidance on that question would be a minimum of $1000.
When I was setting up my LLC, I was advised that under any scenario I needed to be scrupulous about avoiding any appearance that the corp is simply a personal alter ego. That specifically meant not engaging in personal transactions with the company, such as personal use of company assets or routing personal expenses through the company (e.g., using a company credit card for personal expenses even though I might be reimbursing the company in full for those charges). Corporate structure was a minor component afterwards, because if you didn't hew to those concerns, the veil would be vulnerable under any structure.
To the extent that corporate structure was a factor, C Corp offered the highest protection, followed in order by S Corp and LLC. But he hastened to add that corporate structure was almost irrelevant if there was a dirty relationship between business and personal activities. Even with a C Corp, if separation wasn't maintained, the corporate veil could be pierced with roughly equal effort.
At the same time, the administrative requirements were greatest for a C corp and easiest for a LLC. In the end I opted for LLC due to simplicity.
With all of that said, the liabilities in my LLC are about two orders of magnitude larger than what might accrue in your situation. In my LLC, if I have a project go south, the liabilities could easily be in the millions of dollars. So, I'm insured up to $10 million. My LLC has only minimal assets, so my concern is making sure my personal assets are protected beyond $10 million. I am very scrupulous about keeping a firewall between the business activity and my personal activity.
Your risk assessment will likely be different. Specifically, what is the downside risk if your corporate veil gets pierced? Given what you've stated, I think you should assume that an opponent would be able to demonstrate that your company was set up to facilitate a personal interest while outplacing the associated liabilities. But those liabilities are probably not any greater than what you would have faced had you not used a corporate structure. And would the amount at stake be large enough for the other party to expend the legal fees associated with attempting to pierce the veil?