Get a HELOC; you can pay it down when you have extra cash, and draw on it in a heartbeat when a new deal comes your way.

This particular rehab is going to be close on funds. my thought is a heloc with the two paid off houses. and this will provide me with the funds I need to do either another purchase or to finish rehab.

Go to your local banks, and see if you can get a HELOC on the property.  

This got me thinking however...I'm curious, how viable of a strategy would it be to buy a house that needs work and fix it up with the fha 203k loan instead, then take out a heloc for the value you've built up by doing the necessary work on the property and potentially using the money from the heloc for a down payment for a second rental property?

I am purchasing a 4 unit property that will need significant renovations that I expect to take a total of 8-10 weeks.I will be purchasing it with cash (mostly my HELOCs) and doing a refinance when it is renovated and occupied.

Here were my thoughts.I have about 20k cash and was thinking of using that plus a HELOC on my current residence for another 45k to get started. 

I just refinanced my own home and did a HELOC and they did the whole thing for free as a repeat customer.

Paying for the house with a HELOC for $60k at 3.8% interest only payments ($190/month). 

This will give you advantages when/if you want to refi out of that loan or get a HELOC, you have the right to use the equity. 

I have a heloc on my primary for about 60k of 100k @3.5%.