More detail from the Vermon COVID page:
Quarantining at Home Before Coming to Vermont
Depending on how you travel to Vermont you may be able to quarantine in your home state before coming to Vermont.
Quarantining Before Coming IS an Option
If you plan to travel to Vermont in a personal vehicle (including a rental vehicle or private plane), you may complete either a 14-day quarantine or a 7-day quarantine followed by a negative PCR test in your home state and enter Vermont without further quarantine restrictions. Continue to quarantine until you travel to Vermont.
When you travel to Vermont, only stop when necessary (like for fuel, food or rest). When you stop, wear a face mask or covering, keep a 6-foot distance from others and wash your hands often. Stay home and do not travel if you are sick.
Quarantining Before Coming is NOT an Option
If you plan to travel to Vermont by public transportation (plane, train, bus) or from further than a direct car ride, you must quarantine in Vermont. You may complete either a 14-day quarantine or a 7-day quarantine followed by a negative PCR test, in a Vermont lodging establishment or with friends and family. You must stay in your quarantine location for the duration of quarantine other than to travel to and from a test site.