It is a hard pill to swallow, but the fact is that not everyone has the right psychological makeup to be a successful investor; recognizing that and NOT investing can lead to riches or really prevent massive losses. 

Commercial loans traditionally require more down payment and offer shorter terms.

Wholesaling, perhaps, but certainly more difficult than the get-rich-quick gurus claim. 

There are some tricks to disguise that credit though.Why not go traditional loan? 

Was anybody else angry after reading Rich Dad, Poor Dad?

My main question is how to go about purchasing an off market deal with traditional financing.

Here are 2 different reasons that sellers ask for cash only; Speed of Transaction- Cash only closes tend to close quicker; Property won't pass inspection- Seller knows that a traditional bank won't finance the property;  

Also one more tidbit from rich dad is to buy investments that you love so you'll take care of them.

As part of my answer to your question, I would actually refer you to the part of David's book where he describes "Traditional Tom" and "Mastery Mike" (pgs 37-50 in the hard copy).

Most lenders won'r take a 2nd position lien with a HELOC, so you may want to entertain a traditional non-cash out refi with a new lender AND get a HELOC as well.