My credit score is 683 and rising. 

The issue is I want to continue investing but I can not get financing from a bank because of my credit score and I am nervous about hard money lenders.

It could cost you thousands of dollars to raise your score 100 pts a few months faster.New credit sources will temporarily lower your score, so plan when you want to get that mortgage and don't open any new accounts for a few months before.

I have three jobs(one full time and two part time), a 735 credit score and a low DTI ratio.

I was told their lending guidelines are based on credit scores and debt/income ratio so YMMV.

You have the option of a 15, 20 or 30 year term.For A Fixed Rate Purchase, Investment properties, Mortgages 1-4; A SFR requires a LTV of 85%A MFR requires a LTV of 75%A minimum credit score of 620For A Fixed Rate Purchase, Investment properties, Mortgages 5-10; A SFR requires a LTV of 75%A MFR requires a LTV of 70%Minimum credit score of 720Here are some answers to FAQ as well;1.

That sounds like a great idea, like a long term version of airbnb.

Can anyone recommend a simple way to accomplish this (aren't there websites out there that the tenant to pay for the background check/credit score and then that info will be sent to me?).  

I need to research how to score some real real estate. 

Credit Score above 660 I believe (if you don't have a credit card already get one immediately and start using it for gas and groceries - set up automatic payment from your checking account and DON'T MISS A PAYMENT!)