Cakovec is only 100 km away from Zagreb, on the major route that leads to Balaton and Budapest. We went there by Lars Gabriel Svensson (that's my car, in case you didn't know) by taking the A4 motorway (Zagreb - Gorican).
Lars loves to drive on empty motorways so we were in Cakovec in less than an hour.
There are several direct trains daily from Zagreb to Cakovec. Depending on their range and route the trip lasts between 2 and 3.30 hours. In general, trains that go via Koprivnica are faster than those going via Zabok.
There are also buses going from Zagreb, but since they mostly take the local road and stop at every street lamp it is not much faster option.