Though I know you mention it as being too expensive, it seems the Carnegie Mellon Online course is probably the cheapest commercial option. I’d be happy to be told I’m wrong. The free online robotics course materials are of varying levels of detail, and none appear to use the VEX EDR platform or RobotC. Again, I’d be happy to be told I’m wrong.
You only have to stay a tiny bit ahead of them, and (of course) it doesn’t hurt interested, motivated students to know their teacher is learning too. So come back here and ask specific questions, including looking for sample code and explanations for how the sensors work. You’ll have to turn that into class materials if you want something formal to present. But you could always give back to the community by making it available to other educators in your situation.
I see the CM course listed as $499 at this link. http://education.rec.ri.cmu.edu/training-vex-online/ That was after a very brief search, so I could easily be looking at a different course than you found. But this course might help. Unfortunately, it’s a slow-roll class, one meeting per week unless you’re in the Summer Session.
RVW is great, but it doesn’t include much in the way of instruction about sensors. And, in my experience, the kids aren’t nearly as impressed with moving something that looks to them like a bad video game with inefficient controls. Some of them will get excited about it, but nothing matches the feeling they get when lines of code make real hardware move.
Looks like your school district spends around $20,000 per student. Mine spends half that. I understand much of that is simple geography; LI is more expensive than bourbon country. But we work to get donations from a few sponsors just like it seems you’ve done for your VEXIQ club. Also, there were some grant programs available to help get VEXIQ off the ground. Not that you need that; looks like you hosted a VEXIQ event recently, so you’ve got that down.
One resource could be teachers with VEX RC teams near you. It looks like there are at least two strong programs near you, at Jericho High School (team 9932) and Massapequa SD (team 9458) both are doing well; perhaps their sponsors would be willing to arrange a mentoring session between their high schoolers and your middle schoolers as part of their STEM community outreach.
But no matter what, come back here and ask for specific information and help. You’ll need to say what sensor you’re working with, and it will be best to start a different topic for each request. Overall, most sensors we have available aren’t difficult to use, and examples and explanations are available for everything VEX has to offer.
[edit: Just to be clear, I have no affilition with REC F, RobotC, VEX EDR, IFI, etc. I’m just a parent, mentor, and coach.]
[second edit: changed “CM” to “CM course”]