Purchase price: $85,000 Cash invested: $46,500 This property was just acquired, part of the investment was in leu of payment for work completed on another project.

I'm a first time buyer.Here's what I show my clients to help them decide if buying down the rate makes sense.In your scenario, the difference in your PI payment @ 6.275 and 5.75 is $54.71.

Having a mortgage payment plus needing to pay an extra $1k/mo towards this TSP loan will crush any cashflow you had hoped for.  

If I take those out like a HELOC how do I actually pay that loan back as I'll still have a monthly payment for that loan? 

I would be looking for something in the 200k range and have anywhere from 100-130k for a down payment. 

If you are locked in at a three-handle, I would HELOC the equity and use it as a down payment on a new deal.

By doing so, from her perspective, if you miss a payment she keeps your 70k and takes the house back so thats really good protection.

If it will be an investment property, you can use a DSCR loan where all you need is the money for the down payment and to close and credit score depending on the factors below. 

This takes into account factors like mortgage payments, vacancies, HOA, and so on.

I think we can all agree, we're not going to see the double digit appreciation we saw in the early 2020's.