advice 4 a novice plz

little time and 2 much info plz help! I am wanting to build an economical but sturdy power boat for charting fishing off the coast of coasta rica. I plan on leaving in a couple of months and boating from a texas port all the way to panama canal. I am looking for something at least 25 to 30 foot long but with so many articles, methods and materials not to mention designs I am going cross eyed and mad. perhaps someone with experience could give me there recomendations i really want to go with diesel inboards. i have been looking at designs for walk arounds, center consoles and cabin boats any advice i get would be appreciated i'm looking for economics, strength, and simplicity of building but dont want to sacrifice speed comfort and functionability where not neccassary.