It has been a rental for about 3 years with a positive cash flow.

You will learn a LOT about land lording real fast in a position like that. 

After this, only money out of pocket will be closing costs.At this point you own 30% of the equity in a house, have established a positive cash flow, and are prepared to begin the next project.STEP 6.

I  have had unsolicited offers of 150k, so I am in a good position if I just simply cashed out. 

As you buy properties and built more equity, you will be in a position to need them.  

.- My payments (PITI + HOA) total $700/mo, but I rent the property for $1,200, so it has $500/mo in positive cashflow.

If you have equity in this property you have negative cash flow not positive. 

There's a cool meetup the 2nd Saturday of every month that might be perfect....no sales, just a bunch of people in similar positions as you trying to figure it all out and sharing resources.Have you started looking for properties to house-hack yet?

As long as the property value go up, and you can maintain positive cashflow, you are okay.Overall, higher risk, and you will need an exit strategy when market values go south.Terry

I'm trying to have all of my factors in order before I make an offer so that I present one that would benefit both myself and the seller without putting myself in a bad start position on my investing journey.