Although I've been investing in and improving multifamily properties since 2000, I decided to go back to school and get a Bachelor's Degree in Construction Management from BCIT (I already have my Red Seal in Carpentry).

I have around ~35-40k as of right now that I could invest.

Mostly because the GF doesn’t want to hold the 40k, she wishes to invest it asap.

Does anyone have any advice as I am just starting out on my real estate investment journey.

Start by reading the Ultimate Real Estate Investing Guide: https://www.biggerpockets.com/guides/ultimate-real-estate-investing-guide/introduction2.

Short answer is as little as possible.The long answer is it depends on the deal.Typically you end up in a subject 2 situation when the current owner has little or no equity in the property, the current advantage of subject 2 properties is that most mortgages are below current market rates.Keep in mind when acquiring a property subject 2, in most instances you are not notifying the current lender of the change in ownership, and most if not all mortgages have a due on sale clause, which is the lender's decision if they want to enforce it or not.I personally like the idea its a great way to get investment properties with low rate loans, that with most likely appreciate in the coming years.

Let's just get the property furnished, a hot tub installed, and start making some money!  

I’m looking at investing outside of California; mainly Kansas.

I want to help my son get off to a great start but I am also concerned what cosigning will do to my debt to ratio and I have been circling real estate investing for the last few years, ready to take a shot now.

@Ken Mull Yea  @Zaina Jouejati is right on the money here.