I see quite a few propellants fueling it: oil dollar position is being challenged, a few countries ( Russia, China, Iran ) have started to settling trade in local currency.

general trading principleswhat will the business actually be doingWho puts what in?

One thing we never want to do is trade the market.

But I also can’t just trade my time for money constantly.  

This is true even under the TCJA, with the reduced C Corp tax rate and assuming the business is a "Specified Service Trade or Business" the owner is phased out of the 20% QBID (i.e. the worst case scenario for an S Corp under the TCJA).I find C Corps only make sense in very limited fact and goal patterns (e.g. foreign ownership, when a company is anticipating going public, and/or when owners want heavy fringe benefits).Don't forget you get taxed when you extract capital from a C Corp -- either via salary or dividends. 

@Brian Watkins Be careful when choosing to use a Quit Claim Deed:A person receiving a purported real estate interest via a quitclaim deed may receive no legal right to the property whatsoever.

It isn't a dollar for dollar trade between your cost and your tax savings.

@Michael BlackwoodThere is no difference in taxation between an IRA and Solo 401(K) on trade or business income generated from a short term rental. 

Just make sure you pull permits for any work, make sure every trade has liability insurance, AND that they either have workers compensation OR sign a release of liability for worker compensation.

The reason prices are so high is that these trades people are so busy.