When I spent a month in Europe in the summer of 2019, I ended up visiting 43 Dutch zoos as part of that trip. The day I was at
Burgers' Zoo I didn't see any other facility, as that is a world-class establishment that deserves attention and time spent there can range from 5 hours to an entire day. However, Ouwehands isn't nearly as big and can be combined with other zoological facilities.
On August 4th, 2019, I spent 2-3 hours at
ZooParc Overloon in the morning (a very nice zoo!), then I drove an hour to
De Paay (probably an hour there max. as it's the worst zoo in the Netherlands), then I drove only 10 minutes down the road to
Aquazoo Leerdam (a tiny aquarium) and finally I drove 40 minutes to
Ouwehands and I ended up staying 3 hours at that ABC mammal-friendly zoo. Since then, they've added new exhibits like Bonobos, but Ouwehands is probably a 4-hour zoo at best. The key would likely be a rental vehicle, which speeds things up considerably on trips.
If you want to know anything about the 43 Dutch zoos that I visited, then all the information is on this thread in terms of the list of species, or time spent at each zoo. You can even use the search button to quickly look up a facility. Here you go:
Snowleopard's 2019 Road Trip: Netherlands, Belgium, France & Germany