That’s a tough schedule. That works out to be about 7 weeks worth of face-to-face courses, right? I almost wonder if it would be worth your time to pare Unit1 way down to just the essentials (problem solving process & the input, storage, processing, output model) and some community building then focus on Unit 2 and the HTML & CSS side of things. Students get very excited about the “making” aspect of Unit 2 and might really be motivated to work even between your sessions.