you might want to try Plato: Apology
with commentary, text, and vocab by James J. Helm. The book has lots of commentary/glossing next to the text, and a virtually complete vocab section in the back, in addition to sentence diagrams of some of the more complex sentences, and full principal parts of quite a few verbs. I'm reading this currently in a second year greek class - we read xenophon's anabasis first. This book does a really good job with help in the tricky bits, esp. in the beginning (remember that relative pronouns may be attracted into the case of the omitted antecedent!) and has tons of references to specific Smyth passages. There are a few people in my class who started off with Mastronarde, i started with H&Q.
While my experience with a *variety* of texts is limited, i find this book to be pretty straightforward and understandable.
(it's a little pricey for being such a slim book, but it's well worth it!)
hope this helps, and good luck!