The garage has been closed off and intended to be turned into another unit at one time, but previous owners had stopped after installing a new furnace and AC for unknown reasons.

Then about 18 months ago the tenants stopped paying rent.

It sounds like there really is no personal risk if there is a default and doesn't affect your ability to borrow personally moving forward.

Also, you don’t get to borrow 75% “of the equity”.

Now days, if you're looking in the 300k range, unless you're a disabled Vet, that freakin crushing 3+ points in VA Funding Fee for a "multi - user" borrower, which gets stacked/ financed on top of the loan, that you also pay interest on too, is not always the best way to go.I just started following the Military Investors on BP as prior I haven't ventured out of the Florida Real Estate Q&A forum on BP. 

I haven’t let no money stop me in the past so I just need to keep moving forward and scaling up.

I personally would not co-sign or co-borrow with anyone, other than my wife, without a legal binding agreement addressing default or dissolution of the partnership.

You can try to borrow from friends and family and cut them in on deal.

It's right next to Lake Michigan (I can see the lake from my room), the bus stop is right in front of my doorstep and the train is only a 7 minute walk.

Your property will only foreclose if you stop making the mortgage payments.