I had planned on buying a new primary residence  that needs a rehab that i can get way under market value.

land sale is in Northern PA, but we are currently NY residents. 

my condolences on your recent lost.there are a few ways you can do this, as mentioned above you can take a heloc on your primary residence which will give you a second mortgage, first mortgage payment wont be impacted. you can do cash out refinance which will give you one mortgage and payment. it will pay the old mortgage and give you money in your pocket to pay for the rehab.or you can do a renovation refinance which is similar to cash out refinance but we would contractor involved  as part of the refinancing and they are paid through the loan

Holding a piece of real estate over time that a resident provides every dollar you will need to cover the holding, maintenance costs, and financing costs, all while it goes up in value, is the same with a property marketed "turnkey" as it is with any piece of real estate. 

Quote from @Khon Kounbandith: Investment Info:Single-family residence fix & flip investment.

Well if you go together it could split it and get basically nothing - spend $2-3k file a lawsuit and get a judgment you are first in line… Also in many instances you can slap that judgment on his personal residence as well and foreclose on that.

In some cases, after running the numbers, I’ve even faced potential negative returns, causing me to miss out on promising deals here in South Florida.That brings me to my question: I currently own two homes—one is my primary residence, and the other is a rental property.

Hello,I have noticed that more and more property managers are charging tenants ~2-3% of rent + $30 as admin fee/resident package/utility package.

I don't know your living situation but if your paying x,xxx for rent or a mortgage and instead by living in one side and renting out the other you will be paying y,yyy instead and y is less then x that's great, especially if you can rent out your primary residence and make income there too. 

Your income isn't high enough for it to make sense as a rental and the closer you get to your residence limit the greater pressure you will have to sell it before losing your exclusion in whole or part. 500k right now can make $15k per year income with zero maintenance or tenant risks.