The main property will be my primary residence.My biggest question is, what kind of foundation would you use, (that is to code and will pass inspection/permits in Charlottesville) that is either relatively easy DIY or cheap to outsource.

If you are borrowing for renovations, you will likely have a draw fee in the $100-300 range per draw.Selling costs: biggest one is commissions.  

Where people want to live will drive rents, revenue, and appreciation. 

What are the biggest pitfalls I should look out for? 

SPECIAL RULES FOR SECTION 1031 LIKE-KIND EXCHANGE TRANSACTIONS, page 135 states:". 01 Taxpayers are provided the relief described in this section if an IRS News Release or other guidance provides relief for acts listed in this revenue procedure (unless the news release or other guidance specifies otherwise)..02(1) The last day of a 45-day identification period set forth in § 1.1031(k)-1(b)(2)(i) of the Income Tax Regulations, the last day of a 180-day exchange period set forth in § 1.1031(k)-1(b)(2)(ii), and the last day of a period set forth in section 4.02(3) through (6) of Rev.

My biggest fear is that if I ever were to quit my job, I would no longer be able to invest in more real estate (not sure if I would qualify for loans as easily). 

It's the biggest unit of the 4 with the highest rent.What can I expect with this tenent?   

This was during the biggest run up in RE prices since FOREVER.

And you have the biggest mastermind of all in BP.. 

48,000/300,000 = 16% ROI60,000/380,000 - 15.7% ROIAppreciation:Renovated single family = 33% appreciation potentialConvert to Quad = 31.58%So in both calculations your percentage return from gross revenue AND appreciation is higher renovating the single family.