The absolute first cut for these HAs are academics: GPA, ACT/SAT, rigor of curriculum. What are your stats in this arena?
The hot time for D3 recruiting is as a rising senior; Ivies begin as rising juniors, but continue through the next summer.
Are you sure you feel academically challenged at a JUCO? I know of no JUCOs which are on the same level as UC or HA D1s; you're at two different ends of the spectrum.
Any HF camp will be chock full of D3 and D1 HAs; don't limit yourself to specific HAs yet.