These maps of the Beatrixpark are available:
This is the map (click for magnification) as it was made a few years ago. It is no longer entirely correct, as there has been a lot of building going on in the south part of the park. The city is developing new maps to replace the ones that are now on display.
Map of the RAI-area: RAI conceptprojectbesluit
Map of the plans for the Prinses Irenebuurt :
The area in and around the Prinses Irenestraat has its own site : http://www.irenebuurt.nl
On the site of the city of Amsterdam you can find several maps, for example with an overview of areas where it is allowed to barbecue, (BBQ is NOT allowed in the Beatrixpark) or walk your dog. : http://maps.amsterdam.nl
Map showing where your can walk the dog without a leash: