I’m not sure this could work, but everyone else is doing weird ideas, so let’s consider another one.
Remember Lancastrian methods of education from 19th century England? Part of the idea was to keep small group size, and economize on labor, by having the students teach each other, typically with the older students instructing the younger.
Here is my suggestion: have students use an app to arrange in-person meetings, in groups of five, for periods of a few weeks running. Social distancing and masks can be applied as conditions at the time dictate. The app will match students on the basis of stated interests, and sometimes by other methods too, such as levels of mathematical sophistication or if you wish cultural diversity. The app also will tell them where to meet on campus, all classes being held outside.
Some classes would be led by professors, but there are not enough professors to go around so many others would be led by the more senior or otherwise better informed students. Professors and TAs could rotate across various groups if so needed.
All students are given free iPads, connected to campus wireless, and sometimes those iPads would serve as collective blackboards for the small groups.
Central admin. or departments could impose curricular structure in advance, or within a topic area particular assignments might be generated by “Unconference” methods, for instance the students might agree to read a particular book or essay, or to all learn a particular skill. To the extent overseeing faculty are scarce, you can try having the students themselves finding the relevant teaching materials. Very good groups would have the option of continuing for further weeks.
Start in August, keep on going until its gets too cold, they did it at Valley Forge and people learn in the desert and tropics too. Many of the meetings can be short — say 45 minutes — and you can privilege the more valuable majors with locations in the shade. Put up as many tents as you can.
Every class has a supply of back-up YouTube material, and associated testing, for when the weather is bad, or for when the semester has to end.
For the final semester grade each student writes a 20-25 pp. paper about what he or she learned through these units. Professors and sometimes TAs would grade those papers, and do note this is not an insuperable grading burden. It rewards the “did you learn anything useful at all?” approach, rather than “did you manage to sit and suffer through through all of your boring classes?”.
I suspect it feels too much like chaos to a university administrator, but perhaps that is an argument in its favor?
You will note that this method, for all of its learning uncertainties, has two big advantages. First, it really does prioritize the health of everyone involved. Second, students still have lots of contact with each other and get to enjoy some version of the campus experience. The interactive groups might even provide a more engaging campus experience than did the status quo ex ante, keeping in mind that some schools will combine this method with the abolition or radical paring down of dorms.
Addendum: Hand out free diapers, all other plans have that issue too.