But I'm also thinking about that phrase "Live/Rent where you want, invest in where it makes sense" and I'm not entirely sure if buying an apartment would make sense right now.I'm a little late to commenting on this, but just an additional thought based on your statement of investing where it makes sense...it may be worth it to find a super cheap place to rent and just amass funds to either buy in the DMV or in another market where you could cashflow right away.

They are cheap and inefficient, but they are reliable.Heat pumps work really well as long as you have a good way to distribute the heat.

If you're responsible, its like cheap private money (that will wreck your credit score lol)

Were I 18 and in your position, I'd do the following:1) pester your mom to introduce you to her more established clients2) if #1 is successful, throw yourself at their feet.

If it was less, I'd throw it into an IRA. 10% should be easily achievable if not dwarfed by higher numbers in most markets.

For my money, I want to pay as little extra towards very cheap debt as possible. 

In terms of rehabbing the property, the workflow can range from throwing a coat of paint on a wall or two, to an entire gut of the mechanicals, windows, siding, and flooring. 

The first thing to accept - Good contractors are not cheap and cheap contractors are not good.   

  $158k will easily be enough for a downpayment on another property.Even though single family homes are fairly pricey right now, apartments and REITS are actually relatively cheap right now. 

I use bluebeam for takeoffs. its pretty cheap and super easy to use.