I have a potential client who wants me to do a total rehab of their residence but I have heard horror stories in that payment takes a while and contractors end up being over leveraged or needing to stop work due to slow payments.

The only thing that slowed me down was waiting on inspectors. otherwise I would have did it alot quicker.

If they're slow and full of empty promises, you move onto the next guy.

Go slow and build a case. 

Remember real estate is generally a get rich slow game.

@Frank WongYes I probably do need to slow down and get a little more savings so I can get my foot in the door properly without trying to force anything.

Look at other properties in your area on Vrbo and Airbnb and see if they are dropping their prices in order to get renters.It may be that you are just going to have to make your money during your peak seasons.I only have a couple months that are slow.

They listed it around 8/21 and it is still vacant, and they are keeping me in the dark about progress and extremely slow to respond to my emails. 

You can let the $12k ($6k per person) grow while you educate yourself and withdraw the money later penalty-free. 

If it's a slow market and you have a hard time finding a qualified renter, then you may consider a longer period but that should be on a case-by-case basis and rare.