Conventional route would work for your 4-unit plan, you on't have to worry about a self-sufficency test going that route like you would with FHA.

Reason I am digging into this question is because making it known that my plan was to hire a builder, that scenario wouldnt suffice in the situation.

In order to secure my investment will a promissory note suffice or do I need a deed of trust or something as collateral in the event I don’t get my $ back? 

I don't think it can suffice as a LTR which is my hesitation. 

@Bryan ChristopherThere are several considerations that can go into the analysis of whether you need an LLC or whether a large insurance policy will suffice.

. - If this is your first and only asset, you likely do not need two entities - an LLC will suffice for now.

I don't want to get too deep right off the bat, but suffice it to say that you can find a way if you're interested. 

Though, like one of the Ford Mustangs Steve Mcqueen drove in Bullitt, in my opinion, every piece of real property is unique, and therefore monetary damages would not suffice, unless the plaintiff requests monetary damages in the alternative. 

I think having a good pension and 4 SFH in california will suffice in replacing not having my 457b retirement money anymore!

There are several considerations that can go into the analysis of whether you need an LLC or whether a large insurance policy will suffice.