Where to invest $100,000 passively

[Aaron May]

My wife and I own 8 vacation rental properties, and have done well with those and have continued to add one every year or so . We just closed on our most recent purchase in September and are gearing up for a renovation in January, which will consume all of my available time and bandwidth for the next 6 months or so (I own a business that is my "day job" and am only willing to commit so much of my extra time as I do have two kids that deserve my attention) . One of my lenders/investors reached out to me and has $100,000 they would like to have me invest. In the past, I have invested their money into my projects, with a fixed guaranteed interest return and it has been smooth and they have been very pleased with the process. This is the first time the money came and found me, it is usually the other way around. 

I am not looking to buy another vacation rental, i'm content with what I have going on in that space. I am interested in going the more conventional rental property route, either SFR or multi family. My market isn't providing much in the way of value right now, property is expensive and rents are stabilized and it doesn't offer enough net positive cash flow to get excited about.

I have researched other markets like Cleveland, Memphis, Orlando and others that do look more promising. I want to stretch the cash out into as many assets as I can. I have structured loans from this investor as interest only for 3 years or so, with principle all due at the end of the term, and that has worked well. I'm thinking of doing 20-30% down for several SFR's, with a target cash flow of +$300 or more each, with a 3 year interest only loan at 6% and a balloon at the end of the term, with the plan being to cash out refi near the end of the term to free up the principle to pay him back. I would appreciate any insights that could be offered on this approach as it's new to me and isn't in my area of expertise . Thank you in advance.