New Maine guidelines mandate that out-of-state visitors (except those from New Hampshire and Vermont, and now New York, New Jersey, and Connecticut) quarantine for 14 days upon arrival or show proof of a negative COVID-19 test conducted no longer than 72 hours before arrival. That requirement has stymied many Massachusetts residents, who say they?ve encountered a baffling array of rules among different testing sites, making it challenging to get timely results.