Sure, the south coast of England with Brighton, Portsmouth, Bournemouth, and Exeter is a fantastic region to explore. Here are some travel tips:

Best Time to Visit:
The best time to visit for pleasant weather is during the late spring and summer months, from May until September. The weather tends to be warmest and driest during these months.

Route and Accessibility:
You can easily travel by train or car amongst these cities. Start your trip from London to Brighton (about 1 hour by train), then move westward towards Portsmouth (about 1.5 hours by train), followed by Bournemouth (around 1.5 hours by train) and finally, Exeter (approximately 2.5 hours by train from Bournemouth).

Altitude and Acclimatization:
The altitude won't be an issue, as all these cities lie along the coast.

Accommodation and Booking:
There are plenty of accommodation options available in all these cities. Booking.com and Airbnb are reliable platforms for booking. Book in advance if traveling during the UK summer school holidays or on public holidays.

Clothing and Essentials:
The UK weather can be unpredictable. Even in summer, the temperature can fluctuate. It's wise to pack a mix of both light and warm clothing. Don't forget your beachwear for Bournemouth and Brighton. Carry a good-quality umbrella as well.

Health and Safety:
These are safe cities, but like any other places, keeping an eye on your belongings is recommended. Brighton and Bournemouth can be busy in summer, so be careful if you're swimming or sunbathing.

Local Etiquette and Respect:
People in the UK appreciate politeness, so remember your manners. It's also customary to tip in restaurants if you're happy with the service (usually around 10%-15%). Be respectful of local customs and be mindful of noise levels if visiting quiet villages or residential areas.

Enjoy your trip!