Clarification needed: The Changes between I, IV, and V.

Greetings Forum!

My entire guitar experience, which spans a couple of years now, has focused mostly on learning the minor and major pentatonic scales. I've finally gotten to the point where I can find my way around the fretboard "pentatonically" without stumbling too much. I like to go crazy sometimes with noodling around in a given key like E, and I can even throw in a flat five every now and then.

What stumps me, though, is when I change to the IV (A) and V (B), it doesn't sound as good or as smooth as I would like. But maybe... :idea: I should just emphasize the 4th or 5th degrees of the initial key and not change keys to the IV or V. Am I understanding this correctly or do I need to go back a few chapters?

Incidently, I have been reading Noteboat's theory book and it is excellent. Many thanks for a great guitar book, Noteboat.

Also I picked up the Fretboard Logic package after reading Musenfreund's enthusiastic recommendations for it, and I really like it.