Recently had great experience travelling solo in a group to spiti.
I booked a female only tour to spiti. Initially I was really skeptical about the iternary being very hectic. But I managed and very happy with the stay/guide/food. I went with juswravel; some people have had mixed experience and i think a lot depends on the guide. I feel like I got really lucky with everything. The place was amazing and the trip was also uneventful. Initially had some problem with adjusting to the group but they turned out very understanding towards your boundaries and we vibed well. We didnt even had any disagreements on the seats of travellers which we chose amongst us.
Learnt a few life experience from my room mates. And mostly spiti roads healed something inside me. It was an 8 day trip.
However I do believe luck also has a factor and i had no cases of motion sickness. Even if food,stays are good we didnt have any challenges regarding road block and bad weather. Every day we had a lot of time to explore.
Trip cost :27 k
Extra food cost for lunch : 2k (approx)
Gifts :2.5k
Delhi to delhi ( entire commute was included : volvo two way and a temp traveller)
Triple sharing room ( as luxarious as spiti can get)
Guide and driver were MVP.
Tl;Dr; had a great experience but got lucky with weather and road conditions.