Kant wrote prefaces to his Critiques.... Start with those, if you have not at least read those, then no discussion, especially here, will enlighten you.

And until you do, you're better off not trying to "understand" Kant, especially interpretively. In this case silence is not mere more becoming, but as well much more sensible. When it becomes too much to bear (your own self-imposed silence in the face of a lack of information/knowledge), then perhaps you'll do a little reading. In the case of Kant, you will find it also strengthens your mind.

My friend, I have read Kant for years. I have read the Critiques, and the Groundwork. Yet trying to convey his thoughts to others (esp. with regards to pure practical reason). to enable real understanding, is a most arduous task.

Indeed it is. With some people it's just opening a door, even if it's not-so-easy. With some folks, there is no door. You've read more than I have; I have to believe you already have an answer.

My own approach would be to keep it simple, and you have your text already written: "reason alone guides conduct." Leaven with a good measure of Kant's idea of duty, and the Kantian idea that freedom is freedom to do one's duty. Your auditor at some point will say something like, "I've got it! Just do the right thing!" And this is where the real work begins, although you may allow yourself at this point some feelings of confidence that you will be successful.

And I stick with the prefaces; you know their value. If not for you, then for your student. Beyond that, as the man said, there is no royal road....

I've recently found a book that I think you - anyone who has read a lot of Kant - can get excited about:
The End of Philosophy, Martin Heidegger, trans. Jean Stambaugh, isbn 0-226-32383-8. Not very long at 110 pages, but both potent and accessible, and just difficult enough..

Some of these Kantian ideas....I have noticed that many people need to keep them in their mind constant lest they appear wholly unintelligible. A student can have a reasonable understanding of what is going on (with regards to pure practical reason, for example) after spending an hour with them. YET, see the same student in 1 or 2 weeks after discussing Kant's ideas with them, and they are like "don't understand, explain again!" Although the notion of a "good will" seems to stick....it's just putting all the parts together as a cohesive whole. Thank you for your reference- I looked at that ages ago. Have you read Karl Amerik's works?- I found them extremely helpful too.

A student can have a reasonable understanding of what is going on (with regards to pure practical reason, for example) after spending an hour with them. YET, see the same student in 1 or 2 weeks after discussing Kant's ideas with them, and they are like "don't understand, explain again!" — jancanc

It's not your understanding of what your students' understand that matters so much as what they do in fact understand. Assessment is always its own problem, but set that aside for the moment. How can you engage your students and make them take hold of the basic, available ideas and rebuild in their own minds the ideas in question? That's the challenge for any teacher - that is, if you're trying to teach. Professing - lecturing, telling - all by itself sometimes just doesn't do it.

Ask yourself what you remember about your own experiences when you really learned something. In there is the guide to your answers.

I confess what first arrested me in your OP was the notion of "Intuitive" understanding. It's not altogether a subject that's available to intuition. Maybe you can work out some kind of game that can impart what you're trying to teach. Not easy, but if you figure it out your classes will be better, and a lot less work!