Hello! I'm looking for some advice on purchasing my next property.

I currently have 4 duplexes purchased the better part of a decade ago. They've appreciated quite nicely and along with increasing rents, have decent cash flow as well. Therefore, I'm rather inclined to keep them (or maybe sell just one at the most).

But I am chomping at the bit to get back into the game and double my state-side holdings by buying at least another 8 units in 2018. 

Should I just go ahead and cash-out refinance them all now and sit on that cash until I find something? I've never done such a refi before and wasn't sure what the implications are. I don't have much cash outside of that equity, but I do have a pretty decent credit score.

What's your recommendation on how I should position myself to pounce on the next great deal?
(specifically looking for a multiplex somewhere in Iowa)

You don't have property in hand. Paying interest on loan which you are not using won't be good option. Go to your lender run your figures, prepare the application in the system so you know you will be approved for cash out. Make sure your LO knows why you are preparing cash out application but not ready to cash out. 

I agree with Harjeet completely.  Do your home work and get things lined up but don't refi anything until you have a deal ready to purchase.

If you decide to sell one property look at a 1031 exchange to avoid paying taxes on the capital gains.

Thanks for the replies! 

I suppose it would make sense to get everything set up and refi at the moment I'm ready to move on my target property. Though I'm not entirely sure if it would make much difference regarding interest payments. I do currently have mortgages on all 4 properties and one of them is even a bit above current rates. I suppose I'd have to calculate whether the amount of interest I'm saving by refinancing that one at a lower rate is saving me more than the fact I'd be paying a larger portion towards interest by resetting the amortization schedules for all properties, seeing as I'm around 10 years in on 30-year loans.

I'd definitely go 1031 if I do decide to sell one, though I have the added complexity of being a tax-resident in Japan meaning I'd technically have to report the sale and could still be liable for capital gains; no 1031s here :( - though it would still count for depreciation rollover at the very least.

Regardless, setting up a lender that's willing to offer me reasonable terms is the first step no matter how I think about it, so that's where I'll start.