Sure! Portsmouth, Salem, and Burlington are lovely destinations full of rich history and culture. Here are some travel tips:

Best Time to Visit:
June to August offers the most favorable weather for all the three cities. If you're interested in autumn foliage, September to October is also a good time.

Route and Accessibility:
The best way to navigate these cities is by car. Portsmouth to Salem is a little over an hour drive via I-95 S, then about a 40-minute drive to Burlington via I-93 S.

Altitude and Acclimatization:
Altitude is not a major concern as all the three areas are relatively low-lying. Still, it's important to stay hydrated and rested during your travel.

Accommodation and Booking:
Stay options in these cities range from budget-friendly to luxury hotels, B&Bs, and more. Advanced bookings are recommended, especially during peak seasons or special events.

Clothing and Essentials:
Weather can be unpredictable, so bring layers, and don’t forget a raincoat or umbrella. Comfortable walking shoes are also a must for exploring the cities.

Health and Safety:
Stay updated on weather announcements, especially during the winter. Keep any prescribed medications handy and also a basic first-aid kit in case of minor injuries.

Local Etiquette and Respect:
These areas are rich in history and culture and it's important to respect that. Paying mind to local norms, especially when visiting historical sites, museums, and neighborhoods, is always appreciated. Dress appropriately when visiting religious or commemorative sites.