Easier to make that day a federal holiday, politically, because IMO asking two parties to choose one date is going to be very hard.

With that said, in most states, a workplace, school, university, etc. is legally required to make accommodations for someone to go vote[1], including New York. Even in those states that don't, it would be a shxtstorm of media, etc. if someone was actually prevented. This on top of numerous organizations that provide transportation for someone to go vote.

Possibly even easier: Expand the number of polling places. Double it. Triple it! Imagine if every American only had to walk two blocks to vote. But that would require greater funding from congress which, like choosing a date, seems to be very, very difficult.

1. States that don't:Connecticut, Delaware, Florida, Idaho, Indiana, Louisiana, and North Carolina.