I have read that I can file trespassing paperwork for the individual in the trailer.

But that might be per the individual lender.

Will a lender need to review our individual credit history/worthiness? 

Right now I am looking into a structure like this:-Borrow from an individual with an IRA -> convert to a SDIRA-Make loan interest and principle payable at the end of term (because it's an IRA)-Structure similar to a construction loan with monthly drawdowns of about $5k for the highest probability of success with direct mail-Possibility for an equity component: pledge a percentage of profit along with normal interest in the promissory note (a joint venture)Would this be attractive to a potential investor considering I am wholesaling in California and the average fee is $15k-$20k on the lower end?

I'm open to investing in syndications but don't know if that is better than investing in individual properties at this point. 

If you are a systems oriented individual, then create your system.

A real estate professional is one who:(1)works 750 hours or more in a real estate trade or business in which the individual has at least 5% equity and materially participates, and(2)more than half of the services that the individual provides are in a real estate trade or business in which the individual has at least 5% equity and materially participates.For your common, non-equity W-2 employee who works full time, this makes it not impossible to qualify as an RE pro, but highly improbable, as your average full-time employee works around 2,000 hours in a year, give or take. 

Even then you have to do the legwork up front to vet the sponsor and individual deal.

Or if they looks at the price of individual units year over year...but both of those require a lot of work to get those data.

I am a highly motivated individual who’s looking to get started in wholesaling.