Don't forget to visit the parks in Haarlem. Haarlem has many of them and some are very pretty. For example the Englandpark in Haarlem-Schalkwijk. It's green, you can see a lot of birds here and enjoy the peace and quiet.
Reinldapark is nice in every season, in winter too. You can walk here, go cycling here, walk with your dog or you can go horsebackriding here. (You can rent a horse at manege 'Elviera/Aad' at a landroad nearby. You can only rent a horse here when you really know how to ride).
In summer it's very nice to visit the recreation area of Spaarnwoude. It lays in between Haarlem and Amsterdam near Halfweg. You can picknick here, go swimming in the clean water, go rowing in a boat on the water, go kiteflying or just take a lazy day in the grass surrounded by trees and nature. It's also possible to go cycling, walking or horsebackriding here, because the area is very big.
Around and in the Englandpark is a lot of water. The river Spaarne runs next to it and big ponds are to be found on the other of the park and in the park.
Go for a stroll in the Englandpark, you can take your dog with you if you like. Also you can go here by bike when you want to.
Also the Reinaldapark is very nice. When it freezes you can go iceskating here (only do this when it freezed strongly for several days and when you see a lot of other people iceskating here).
Tips for the best sunsets: ponds in local parks, the river Spaarne and great open fields have to nicest sunsets to photograph.