Absolutely! Planning a trip to Shimla, Manali and Amritsar is delightful as they all offer unique experiences. Here's what I recommend:

Best Time to Visit:
The best time to visit Manali and Shimla is during the summer months (March-June) for pleasant weather.
Amritsar can be visited almost all year round, except the peak summer (mid-May to end of June) where it is very hot.
Winter in Manali and Shimla can also be an entirely different and beautiful experience if you enjoy snowfall.

Route and Accessibility:
You can start your trip from Delhi. First, head to Shimla which is about 7-8 hours drive from Delhi.
Then, travel from Shimla to Manali which is about 6-8 hours by road. From Manali, you can drive to Amritsar which is approximately 7-8 hours.

Altitude and Acclimatization:
Shimla and Manali are at higher altitudes. You may experience some breathlessness or mild headaches. To minimize discomfort take it easy the first day and stay hydrated.

Accommodation and Booking:
Book your accommodations in advance. There is a wide range of options from budget to luxury. Homestays are also a great option for experiencing local culture.

Clothing and Essentials:
The temperatures in Shimla and Manali can drop in the evenings so take warm clothing. Remember to pack comfortable walking shoes. For Amritsar, carry light airy clothes, a hat, and sunscreen, if you are going in the non-summer seasons.

Health and Safety:
Always take travel insurance. Don't forget to pack your needed medications. In places such as Shimla and Manali, road conditions can be treacherous so ensure you are safe during travels.

Local Etiquette and Respect:
Respect the local culture especially when visiting religious spots. In Amritsar, remember to cover your head at the Golden Temple. Dress modestly and take off your shoes where required.