The problems with in-person voting will be acute in the states which have engaged in voter suppression. Because an ideological Supreme Court decided in 2013 that it was fine to gut the voting rights act, certain states--North Carolina, Texas, Florida, and others---have shut down hundreds of polling places, mostly in minority areas, causing hours-long waits and long trips to the polls. In Louisville, Kentucky, a city of 600,000, there was only one polling place in the recent primary. Wisconsin had trouble finding poll workers--a position held most often by elderly, retired people wanting to earn a little extra money at a temp job.
Voting machines will have to be sanitized frequently, perhaps after each voter, taking extra time. Fewer poll workers will make it harder to keep enough polls open and will possibly affect early voting time.
I am sure Dr. Fauci, being the kind, compassionate, gifted epidemiologist he is, is assuming that states will eventually get extra funding to deal with all these problems so that people can safely vote in person, but since the Senate left Washington until mid-September, it is unlikely that those funds will be forthcoming.
As a senior citizen, I am torn as to whether to vote in person or by mail. I have been minimizing in person errands, but I do not trust the new Postmaster General, who fired 23 of the USPS' top executives immediately, has no qualifications other than a $2 million donation to Trump's campaign, and owns tens of millions of dollars in the stocks of Post Office competitors.
We are fortunate that our state has a commitment to early voting. Our polling place is a mile away, and once early voting begins, I will watch for a time when the parking lot is empty and pop in.
I do not want to trust my ballot or the ballots of my family to the rogue postmaster Trump obviously found where he stores all his cabinet and Supreme Court picks---the swamps of the Florida everglades.