where to go in amsterdam and beyond

Wow! You have a keeper in that man! Great gift and such a fun excursion...just saw James Taylor at the Hollywood Bowl last summer - one of my favorites and I am supremely jealous that you get to wing to Amsterdam to get to go see him! But I digress...
The weather in northern Europe won't be all that great in March but there is plenty to do for 8 days in Amsterdam - you'll have a few beautiful days but it's a little early for parks/flowers so the indoor activities will have to fill your days. Besides all of the things that are easily searchable in Amsterdam, I would suggest taking time to go to Haarlem. It's a stunningly beautiful, old, well-preserved town. You can get there via public transport in just 15 minutes. You have enough time to rent a car and drive out to the countryside as well for a day. If you don't mind a bit of driving, take the A7 out of Amsterdam, cross the Afsluitdijk (a very long bridge/dike that crosses a piece of the north sea), and go to the town of Sneek. From there you can loop back through the countryside to Amsterdam. There are beautiful windmills, farms, small villages up in this part of the Netherlands (called Friesland). Stop off and buy cheese at a farm, eat pannekoeken, and enjoy the scenery.
For your additional 4 days, since Europe is so cold in March, I would consider heading to north Africa. It's very cheap to fly there, the food is fantastic, and the weather will be beautiful. Head for Fez and stay in a beautiful old riad and wander the medina. As fun as South Africa would be, 4 days just isn't enough time IMHO.
You could also head to Herault in the south of France. Warmer weather, gorgeous vineyards/wineries (Abbaye de Valmagne is my personal favorite), and amazing food and beaches. Stay in the town of Pezenas - amazing Saturday market year round. Very old village circulade with winding cobbled streets, lots of artisan shops, great gastronomy, and small-town atmosphere.
So those are just a couple of thoughts...I'm sure you'll get lots of other equally wonderful suggestions as to how to use your carte-blanche 4 days!

If you are looking for a place to stay in Amsterdam, I HIGHLY recommend Boogaard's Bed and Breakfast - you can find them on TripAdvisor - over 700 5Star reviews. We stayed for 4 nights last year and it was, by far, the BEST B&B we've ever stayed in. Peter was an amazing host & cook. Delicious Breakfasts daily, plus cakes/pastries every evening. It was super clean.

If you have a free day, I recommend the Anne Frank House and a wine and gouda tasting. So much to see and do in Amsterdam. Peter recommended amazing restaurants. He can also help you plan a train trip to Germany or anywhere else from there. He used to be an Opera singer in NYC, but after 9/11 - decided to move to Europe . . . so he is VERY WELL traveled in the area---plus, he lived here in the states for years.

It'll be an amazing trip.

ok...not sure what that means, but i'll ponder it.

If you had more than 3-4 days, I'd say the Seychelles. And you can fly there directly from Amsterdam (although it's a 14 hour flight).

A more reasonable choice might be Monaco. You'd have casinos, wine, food, the French Riveria ...

The Kuekenhof Gardens outside Amsterdam is great: 70 acres of tulips; 7 million bulbs. If they had a mild winter the flowers might be out. You'll have to check. I was there in early April last year and it was spectacular.

If you are going to the Van Gogh and Riksmuseum get tickets online first. The biggest lines are the Anne Frank House, so check out tickets early. It's also in my favorite neighborhood, the Jordaan.
Had the best hot chocolate at the Metropolitan in the Red Light District.
Enjoy!

Fell in love with Brugge, Belgium....not too far away.

Thank you all!! Ive got my tickets to monaco at the bay beach hotel. We are thrilled..Thanks for all the help!