Here is an itinerary as you requested
Day 1 - Reach Manali by morning. Have breakfast and relax for a while. After freshening up, you can start your tour with the Hadimba Temple. After this, you can head out to the Mall road for some grub and a little bit of shopping. The main market is bustling with activity and you will find a number of items from woollen clothes, shawls, local handicrafts and everything you need.
Day 2 - You should head off to Rohtang Pass. It remains open from April to November. It is a two-hour road journey from Manali and you need to set off early in the morning around 4:00 in order to avoid the traffic. The entry passes are available in Manali and you need to get it a day in advance. While returning, you should stop over at Solang Valley.
Day 3 - You can also go to Vashisht hot springs. Soak yourself in the hot water springs in the winters and it feels magical. After this, you can head to Old Manali for shopping and a scrumptious lunch.
Day 4 -While returning, stopover at Bhuntar and you can go for rafting in the season. Otherwise, you can also explore Kullu's market and temples. There are a number of things you can do, depending on your mood and the season.
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