So I looked up the details on what would need to be done. I'm going to summarize those items that really couldn't be done in advance:
1. Skill circuit: This is showing you've got "demonstration-quality" capability in 24 different skills. I'm not sure how you get demonstration quality without having been taught it over some time, but maybe they send out videos to watch and encourage you to practice before you show up?
2. Waterskills: This is 5 skills including timed swim, timed snorkel, timed diver tow, timed float, and equipment exchange underwater. The float alone takes 15 minutes. Swims depend on speed of diver, but should reasonably add a half hour or so of actual swimming time, excluding recovery between "events" or time necessary for logistics. (E.g., doffing/donning mask, fins, and full SCUBA gear as appropriate.)
3. Dive rescue demo. OK, maybe they just got out of a rescue class and can nail this first time out? Or is a demo done? Videos shown in advance?
4. Dive site management: This could be rolled into assisting with classes, I guess.
5. Mapping project. I'm assuming they have to do this on their own.
6. Dive briefing. Theoretically wrapped into a class?
7. Search and recovery scenario. (Basically do the S&R Adventure Dive.)
8. Deep dive. They have to do it with the instructor. I suppose this and item 7 could be rolled into assisting, sort of, with an AOW course? Seems like that'd be pushing it in terms of compliance, though.
9. Re-activate workshop: Either assist with a class, or a mock class. But this isn't something you can rush through.
10. Skin Diver workshop: Same deal. They need a real class or a real mock class.
11. DSD workshop: Same deal.
12. DSD open water dive. Same again.
13. Discover local diving: Same again.
14. Assist with full open water course (pool and open water dives). This has to be a real course.
15. Continuing education course assisting. This has to be a real course.
16. Lead a real dive kind of like you're guiding.
That seems like a really busy two weekends. The most "efficient" I could get quickly adding up is 11 OW dives, 7 CW dives (a couple of which could be added to OW, if preferred, and 1 skindiver session. I'm assuming they could do the skill circuit, water skills, and rescue demo in one horrendous CW session.