a lot of new investors pick the cheapest markets in the country regardless of how far away they are, and how much knowledge they have of them, and I think that's a huge mistake. 

You will make mistakes.

But education starts somewhere, and basic analysis and due diligence will enable the investor to avoid the worst investments.  

Intelligent people learn from other people’s mistakes.

Do plenty of research and find out what other mistakes have been made in your are and learn from them.Both are great options but maybe doing a simple pros/cons list for both STR and LTR.

Choosing the wrong 1031 Exchange Qualified Intermediary to administer your 1031 Exchange could be a very expensive mistake due to the Qualified Intermediary's critical fiduciary responsibilities and obligations through out your 1031 Exchange transaction.You may focus all too often on issues such as size of the Qualified Intermediary, 1031 Exchange fees, interest rates paid, turn around times, branch office locations, and the like, when interviewing potential 1031 Exchange Qualified Intermediaries.

But worst case they should assume you’ve paid it off, helping you. 

If your "estimate" works for you and your "high estimate" is still workable for you, then you can feel confident that if you use good project management practices that you can manage the project to somewhere between those 2 numbers at worst.

Just trying to prepare for the worst.

If I hadn’t been an expert in this market there would have been many variables I would have had to estimate which is a rookie mistake.