Kasol has nothing in there, except for doing camping river side, average restaurants and decent street arts. I'd rather suggest spending 1 night in kasol and next day to malana or chalal if you want lil adventure and make your trip worth..
Kasol is a place with multiple treks. Plus there are multiple places with senic landscapes and all. I'll suggest if you like scenic beauty and all with a bit of hiking and treking then this place is good for you.