Relocating to Nicoya area (San José)

I am a 26 year old Veteran of the US Armed Forces. About 6 months ago I started my research on a new way of life. That lead me to the TEFL program. At first I had not chosen a location but dug into the world of teaching english in a foreign country. After a few months I narrowed it down to 2, 1 of which being Costa Rica.
I recently made the choice to go with Costa Rica and hope a few questions I have can be answered here.
My first visit to acclimate will be from Sept-Nov. Protected content

Paperwork- Passport, Birth Certificate, Criminal History, ___ . I wish to obtain a work permit if I can find a school to hire me. Am I missing any needed documents?

Money (3 months)- I am allocating Protected content per month, equaling Protected content . If trying to live modestly would this get me by?

Special Items to bring- Umbrella, Deet (lots), sunscreen, ____. Any other suggestions?

I have many more questions that I am currently researching. However these few are the most pressing in my mind.
Thank you for any advice anyone can give me!