You will most likely be interested in his “Juveniles”. His juvvies books are not at all taking the reader for an idiot. The only differences are that there are no sex scenes, and the main characters tend to be teenagers. For instance, take “The Puppet Masters” (another Heinlein book butchered by the movie adaptation). There are very few changes between the original edition, marketed as a Juvenile, and the modern one. Mostly, one sex scene was removed, another toned down.
So read “Have Spacesuit, Will Travel”, “Citizen of the Galaxy”, and “The Puppet Masters” — the adult version has the main character wake up next to a woman, whereas the original has him alone.
Now for the “adult” books.
Read “The Moon is a Harsh Mistress” and any Heinlein short story collection your can get, especially “The Man who sold the Moon”. “Farnham’s Freehold”, “Friday” and “Glory Roads” are great classics you'll love.
As for “Time Enough for Love”, I'd suggest to keep it for after you have read these other tomes. The reason is that Heinlein wrote his later books at a time when he was sick and wanted to explore completely different themes — immortality, sexuality and human consciousness among others. Far away from the potent themes of his earlier books. He was running out of time and wanted to get them out, and sometimes they lack a good polish.
Thanks much!