Day 1: Delhi-Haridwar (220 km || Approx 05 Hours)
Activity: Arrival in Delhi, pickup from Railway station/Airport, and travel to Haridwar.
Accommodation: Check into the hotel.
If Time Allows: Visit local sightseeing spots in Haridwar.
Evening: Overnight stay at the hotel.

Day 2: Haridwar-Mussoorie (90 km || Approx 02 Hours)
Morning: After breakfast, check out from the hotel.
Visit Temples in Haridwar: ChandiMata Mansa Devi Bharat Mata Saptrishighat
Afternoon: Drive to Mussoorie.
Accommodation: Check into the hotel and overnight stay.

Day 3: Mussoorie Local Sightseeing
Morning: After breakfast, proceed for local sightseeing.
Visit: Kempty Fall
Evening: Explore local attractions in Mussoorie (Gun Hill, Laltibba, Camelback).
Accommodation: Dinner and overnight stay at the hotel.

Day 4: Mussoorie - Delhi (290 km || Approx 06 Hours)
Morning: After breakfast, check out from the hotel.
Travel: Drive back to Delhi.
Afternoon: Upon arrival in Delhi, transfer to Airport/Railway station for onward destination.
Additional Suggestions: Local Sightseeing in Haridwar: Provide information about the specific places to visit during the local sightseeing in Haridwar.
Mussoorie Exploration: Recommend specific activities or places to explore during leisure time in Mussoorie.
Meals: Specify whether meals are included in the itinerary, especially for Day 01 and Day 02.
Travel Time: Emphasize the approximate travel times to manage expectations, especially during long drives.
Climate Considerations: Advise travelers to pack accordingly, considering the climate of the region during their visit.
Emergency Contact: Provide emergency contact details or local assistance information for travelers' convenience.
Overall, it looks like a delightful itinerary covering religious, natural, and cultural experiences.