Which we only run payroll through our construction company.

Do you have any recommendations on a reasonably priced company/service I could use to establish a land trust and buy the property through it?

That sounds great, but it is expensive, stressful, and really sucks to actually go through it.I would posit the question "What can you do that is really hard?"

We want to buy her sister out of the property, but don’t know where to begin because we’ve only bought 3 properties in Pennsylvania through a realtor. 

I mean what else are they saying for that $7k, "break-through" revelations of genius like pick 1,2,3 wall colors for your units and paint em all with that keeping the paint codes so refresh paint can be done via touchup.....

Helps me save money on my own housing and learn a ton about the business without burning through my cash on the first deal.

The thing I have learned through flipping many properties is that slow is smooth and smooth is fast.Make sure you vet your contractors as thoroughly as you would vet a tenant - I have learned vetting is one of the most important things I can do as an investor.

My plan is to fully rent out the house I have and house hack the next property while still investing in real estate through other avenues.

I've gotten so much help from the forum that I wanted to share a lessons learned and the process i went through with an eviction i had mid last year. 

So, there's a structure through which you can do this (a TIC deed), and you definitely need to consult with a real-estate attorney who has TIC experience to understand how to go about doing this.Now let's talk about what's possible with the numbers you've shared...You presently have $640-840K for a down payment and a combined income of $510K.