Hey Jantey! Winters is the nost amazing time to visit Manali and Parvati valley. Go in January mid, you will find snow (fingers crossed). Yes, its possible to go Manali and Kasol. Both are situated at a gap of 3 hrs (approx.). You can take a local bus till Bhuntar and then a cab till Kasol. Or staright away take a cab from Manali market towards Kasol.