Find an experienced operator wanting to operate in your location.

They also might be local and if you bank with them there might be incentives for lending with themCon: A credit union is restricted on the lending options they can offer (they have limited money to lend) and they might not have another alternative that could be better for you. 

Posters will chime in on recommended strategy but real estate is extremely localized and the fundamentals of the real estate in any given market are what should be dictating your investment strategy not arbitrarily deciding to buy single family homes vs. duplexes. 

@Ryan Daulton  It depends on your location. 

.#1 Better Location Selection:Single-family homes with ADUs provide more flexibility in choosing prime locations within these markets.

You will want to check your local and state laws, I do believe some states cap the amount.

Depending on location or even not, it sounds easiest to find a lender who would possibly cross/wrap enough of your other properties to get what equity is necessary to take down the new B&B purchases.  

A different/maybe possible way to go about it, is to find a plot with utilities on the outskirts of your town (may not be possible, I have no bearing on your local market), then buy a mini home.

@Tiffany Tran This question seems pretty location specific since every municipality has their own rules, I would recommend reaching out to someone who specializes in Philly, or perhaps posting in the classifieds asking for legal help in the Philly area!

At least 25% and some investors I know locally making up to 1000% per year.