Working our on capital stack for a large multifamily development and needing some different options with private debt/equity. I have some soft quotes for bank debt but I'd prefer to stick with private debt if possible...

Boutique brokers can work nation wide also. 

If not, talk to brokers in the market, gather as many OMs in the market and you'll be able to find cap rate.

So I direct market to the brokers, the gate-keepers.

Call a local broker on the telephone and ask that question.

I found my insurance broker, Steadily, through a BP podcast ad, I found Baselane to use for banking through a forums ad, I found RentRedi which I've used as my PM software for years as a sponsored post.

You could also possibly partner with a relative who knows / trusts you to make up for any shortcomings you may have.After that, presuming you have good credit, you can go to a mortgage broker and they will evaluate your credit and financial "worthiness" against their requirements for their lenders to lend to you.  

I think you will see a shift on eliminating buyer brokers. 

Do you think it's best to work through a loan broker and if so, should I look for one that's local to the area I want to invest in?

LTR or MTR so regardless of rent style you can go for the long, mid or short.Dayton, OH and Indianapolis, IN are two great cities that my California customers have found great 2-4 units over the last 2-3 years.