Ideally everyone would vote on election day, at the polls in their town. The poll workers get to see a real live person carrying a real photo ID. They can check to see if the photo ID matches the smiling face in front of them. You can't do that with a mail in ballot. If this creates a backup at the polls, open more polling places.
We don't want to support early voting because last minute changes in a candidate's position can make voters bitterly regret the vote the cast some days before. We want to limit voting to real live people, people who live in the town they are voting in. We do this by insisting that voters register in person, at town hall BEFORE election day and show some documentation to the election officials. To be a real New Hampshire resident, you have to have a New Hampshire driver's license and New Hampshire plates on the car. If you carry some outta-state license and have outta-state plates, you are a resident from outta-state and you need to vote there, not in New Hampshire.
We need an absentee ballot procedure for people who simply cannot make it to the polls on election day, such as members of the armed forces stationed overseas. We have that, although I have never used it and don't know just how it works. We should never mail out ballots to people who have not requested them. Absentee ballots should only be issued to people who have a good reason to need them. Fear of catching Corona virus at the polls is not a good reason. Going to vote is no more likely to infect one than going to the grocery store, and everyone still goes to the grocery store. Absentee ballots must arrive by US mail, with a cancelled stamp, and must be in before the end of election day. After the polls close on election day no more absentee ballots will be accepted.
