If you are coming in from Kasane the best border post for you to use is the Kazengula border post which is right there, and then you only have about 70km drive to Victoria falls along a very good tar road which is also excellent for game viewing.
Depending on your passport you might need to buy a visa to enter Zimbabwe. Please look at out visa page Zimbabwe visa.
There are road fees to pay for your vehicle. Carbon tax varies according to engine size. A 2.5ltr bakkie costs US$15 Road access fee US$10 Insurance for Zimbabwe: US$30
It is best to pay for all of these in US dollars. Hope that helps