Hi Jazzman,
I've been teaching guitar for many years and the FIRST thing that I teach is understanding your ENTIRE fretboard. Start with the 6th (E)string and learn every note on that string, then do the same with the 5th and 4th strings.
As far as the pentatonic minor scale, it's construction is: 1st, m3rd, 4th, 5th and flat 7. The easiest way to learn improvisation is to copy some of the easier solos of the blues masters. I feel this method is the most effective. CCR (Creedence) has some basic but effective solos to copy, many of them in the minor pentatonic scale.
Hope this info helps!
Mike