I am working on the pentatonic scales, by playing the bar-chord (if I can), then the arpeggio, and then the scale. I would think when playing the scale or the arpeggio if makes sense to start on the root note.. is that how you would do it?
On the guitar fretboard, it's a good idea to keep track of the root note in each position and know where it's at, but you don't have to start on it. Instead, just start on the lowest pitched note in each position and play to the highest pitched note in that same position. Then reverse direction before moving onto the next position. This is how I intend for you to play through all examples in my guitar theory book. You're trying to map out the neck. Guitar melodies, riffs and lead solos can start on any note, not just the root.
Remember that the pentatonic scale can be either major or minor. This means that there are two possible notes that can function as the root.