The #1 key to getting back to work (not just in sports) is testing. Having talked yesterday to a microbiologist who works at Ft Detrick, the technology is improving - better and cheaper and quicker turnaround - all have to continue to improve and likely will. If the players (and all the NFL workers really) can be tested twice a week, maybe they can get it done. Obviously, it'll be a PR nightmare if the rest of the country isn't getting enough tests while the NFL is, so the country needs millions and millions and millions of tests. I think we'll be playing this year.
College football might be more problematic - especially for the smaller schools.
They would also have to do one of two other things as well.
The first... isolation of all persons directly associated with the team for the duration of the "season."
OR
Test any and everyone who has been in close contact with those listed above, their family members, associates a friends, family members and friends of the original family members and friends and into an endless line of direct and indirect contacts.
Neither works because in the first instance there are trainers, agents and a host of folks who are necessary but can not be isolated. The second instance is obvious in how it fails to be implemented.