Himachal Pradesh 
Himachal Pradesh is a Himalayan state surrounded by Punjab, J&K, and Uttarakhand states and also the Tibetan region of China along its eastern border. The eastern border area ( Lahaul and Spiti ) are contrasting geographically as well as culturally from the rest of the state. While Lahaul and Spiti is rainshadow zone of cold deserts where most of the people are followers of Buddhism, the rest of the state is emerald green and the people are mainly Hindus. One aspect is common in both the areas though – they comprise of plunging valleys and looming mountain ranges that are breathtaking and heart-stopping all the same.
Mesmerizing trekking routes and magical rivers along with quaint Hindu temples and quiet Buddhist monasteries, there is so much to explore in Himachal Pradesh .
British Influence
During the British colonial period, tourism in the Himalayan states became very systematized, especially in Himachal Pradesh.
In Himachal Pradesh, many important towns of today, such as Shimla, Chail, Solan, Dharamsala, Dalhousie, Kasauli, and Dagshai, emerged during this period. Hill stations were originally built as health sanctuaries for the British army, many of which were later developed as administrative and recreational centres and grew rapidly.
Apart from roads, efforts were also made by the British government to connect the hill stations and plains through railway lines. Shimla, the then summer capital of the British Raj was connected to Kalka through the Kalka-Shimla railway line in 1903 (Heritage Report Shimla 2013, p.17). Another railway line was built during 1926–1929 in the Kangra valley joining Jogindernagar to Pathankot.
Kalka – Shimla Toy Train (UNESCO Heritage)
The Kalka–Shimla Railway is a 2 ft 6 in (762 mm) narrow gauge railway in North-West India travelling along a mostly mountainous route from Kalka to Shimla. It is known for breathtaking views of the hills and surrounding villages.
The Kalka–Shimla Railway was built to connect Shimla, the summer capital of India uring the British Raj, with the Indian rail system. It was constructed by the Delhi-Ambala-Kalka Railway Company commencing in 1898.
This toy train ride is one of India’s most incredible feats of engineering covering a staggering 102 tunnels, 864 bridges and 919 stunning curves.
This railway was added to the UNESCO world heritage list in July, 2008.

Connectivity
Nearest Airport : Kullu, Shimla and Dharamshala
By Road :  All the major Himachal destinations are well connected by road.
By Train : Chandgarh and Kalka

Best Time to visit and climate:
The best time forvisiting Himachal is September - November, March - May.  Monsoon prevails from July to September & the winter months are very cold but popular for snowfall.
For visiting the Lahaul and Spiti areas, the best time if May to October. During the wInter months, many wildlif enthusiasts visit Spiti to track snow leopards.

Itinerary Suggestions 
Short Trip    :  https://www.monkfoot.com/tours/shimla-and-sangla
Longer Trip  :  https://www.monkfoot.com/tours/hidden-himalaya-kinnaur-lahaul-and-spiti

Places to visit in Himachal Pradesh

Kullu Valley and Manali : The Kullu Valley include the towns of Kullu and Manali, with Manali being one of the most popular hill destination and also a hub for backpackers & hippies. However, the Kullu district covers a large area and the Tirthan and Sainj Valleys, which constitute the Great Himalayan National Park(UNESCO World Heritage Site), are also a part of the Kullu district.
Shimla : Dwelling on a panoramic location, Shimla is surrounded by green pastures and snow-capped peaks. Shimla is the capital of Himachal Pradesh and known as the ‘queen of hills’. Annexed by British from Nepal in 1819 AD, it became the summer capital of the British  who chose this cool hill town to beat the scorching heat of the northern plains. The tudor and neo-gothic architecture the colonial buildings built during this period adds a unique charm to this place. Shimla is spread over a 12km ridge with two main roads – The Mall which runs from the far west to the lower eastern side, and the Cart Road which circles the southern part of Shimla
Dharamsala and Kangra Valley : The Kangra region has many Tibetan settlements. Dharamshala (McLeodganj) being the seat of the exiled government of Tibet and and are populated by Tibetan diaspora. However, Kangra has its own  rich history and culture as well that include ancient Hindu temples and exquisite traditional miniature, tea estates and also a toy train line which  unlike the other toy trains of India, is mostly used by the locals only.
Kinanur Valley : Kinnaur is the meeting point of the two cultures Hinduism and Buddhism and the getway to the high altitude deserts of Spiti .  The lower areas of Kinnaur are green and display a amalgamation  of Hinduism and Buddhism in their traditions.Sarahan is known for the historic Bhimakali temple which has a unique architecture. Kalpa, is known the magnificent views of the Kinner Kailash, while Baspa valley covering Sangla & Chitkul is known for its pretty and colourful valley and glistening mountaintops.
Spiti Valley – The Hidden Himalaya
The name Spiti comes from the original word Piti which means ‘middle land’, a kingdom nestled between the larger kingdoms of Tibet and Ladakh. Stark, exciting and primitive, these valleys offer magnificent mountain-scape, rugged beauty of their rocky escapements and the splendor of their snow covered peaks of the trans Himalayan landscape.
A fascinating land of Buddhist culture, remote mountain villages and medieval monasteries, which remains relatively untouched and undiscovered by mass tourism. In the winter, as snow covers this land, it transforms into a magical white landscape.  The vast mountains, deep terrains, the stretch of barren landforms, and patches of green are entirely shrouded in a seamless sheet of snow. It’s a sea of white as far as your eyes can behold.