L84SKY your welcome! I love Friesland, and it gets very few foreign visitors, which on the one hand is a shame, but on the other means it is quieter and still beautiful.

If you don't want to go to a museum, still consider The Hague. It's great to walk around in, you can see the Binnenhof (the seat of the government), walk through Noordeinde, and then go to Panorama Mesdag as suggested: I wouldn't really count this as a museum, but it's a great thing to see. Then walk back through Denneweg, maybe have afternoon tea at Hotel des Indes. And if you have time, to to Escher opposite Des Indes.
If it interests you, you could also visit the Peace Palace (Vredespaleis).

I also love the Veluwe area, but it's not as close as The Hague, and you have quite enough travelling on your tour already. Interesting that they include Haarzuilens. That's a lovely area, well worth visiting.

L84SKY; Friesland is beautiful. An interesting part of the country, where they speak their own language. Also the Wadden Islands to the north of Friesland. If you like to be outdoors, or like sailing, it's a great place to visit.