Yes, they are quite accessible - they are long and quite detailed, so no small undertaking to actually read, but Evans is a decent writer and is explicit in aiming the trilogy at a non-academic audience. As a result, the text doesn't assume you already know much about the topic, and it doesn't get too bogged down in introducing complex theoretical or conceptual perspectives that are hard to grasp. It's difficult to think of an alternative which is significantly more accessible but doesn't sacrifice credibility or scope (or both) - the closest alternative would probably be Ian Kershaw's Hitler biographies.

Yes, they were written with the common reader in mind, in the preface Evans writes:

These three books are addressed in the first place to people who know nothing about the subject, or who know a little but would like to know more. I hope that specialists will find something of interest in them, but they are not the primary readership for which the books are intended.

I read them first when I was 17, and found them more than accessible. The writing is perhaps a little drier and a higher level than, for instance, Antony Beevors books on the Second World War, but I don't see any reason why a non-academic wouldn't be able to find them engaging. In fact, you seem to be the primary audience for which the books were written, and I would highly recommend them to anybody who wishes to learn about the Third Reich. Happy reading!