Depending how much you earn you can step up those savings by getting a side-hustle.

No matter what you do I think you really want to consider renting it out for at least a year to convert the ($130k minus $13k in closing costs, minus $80 cost basis = ) $37k in profit from regular income down to long term capital gains.

Beware of incoming phone calls.

In case helpful, more info on DSCR loans:DSCR loans won't use your income to underwrite the loan.

The current loan would have to evaluate your debt to income with the additional debt etc.

So all of my income goes toward paying down the principle.

If not, you can do your thing and earn more for each deal you close.They are also in Pennsylvania and Florida

Yes, you'll be paying taxes on that income, but it's still better to have it as income than not, just like you're better off earning $80k/yr than $50k/yr, even though you're paying taxes on that additional $30k. 

If you were purchasing this 4 unit as a primary residence you could likely use the rental income on the other 3 units as qualifying income.

Metro Charleston is one of the markets that interests us as well.If you'd be willing to share, what cash flow and cash-on-cash return are you projecting to earn?