Kathmandu is quite the lovely mess, and so part of the charm is walking around and taking it all in. There’s a hectic tourist area in the center, from which you can simply walk to the main temple sites in the city.
Durbar Square is where most start out, with lots of places to visit, and all the roads surrounding it are worth exploring. Lots of temples and worship, old rundown colonial buildings, and busy local and tourist markets, with the occasional museum, some dealing with the consequences of the brutal earthquake and the restoration efforts.
I spent about half a day walking around and checking out all the attractions, also chilling on rooftop restaurants.