repayment of loan with cashflow

[Tom Server]

So not sure if this makes any differences for tax reason but

i was thinking of using my 401k money as a loan towards the down payment for a multifamily rental. I don't plan on opening a LLC .. Could i take any of the left over cashflow and transfer to my personal account and use it to pay the 401k loan back? I know the amount of cashflows isnt always going to be the same but i would if their is a positive, i would like to use the funds to pay back the loan

or 

could i set up a checking account with automatic payment to the 401k loan from the left over cashflow deposited from the leases ?

does it matter either way which way?