How good is the game viewing and weather during early April? Highly considering Elephant Plains for my trip.
April is a true shoulder season month. Think of October in Toronto. Remember that the wildlife, with few exceptions, pretty much stays around the same area all the time. The variables tend to be weather and vegetation.
So, South Africa winter months - June, July, August - have the best sight lines because the vegetation isn't as dense. On the down side - shorter days.. sometimes quite chilly, especially early morning on the AM game drive and after nightfall on the PM game drive. Vehicles are topless and only some have side panels.. so you are exposed to whatever the weather brings you.
If April is the month that works best for your schedule, I see no reason not to travel then.
Just avoid Easter time.
I like short days/long nights during the winter (May-August) because you get up before dawn and dinner is about 2 hours after sundown. So during winter, you get a pretty good night sleep. Summer, not so much.
Unless you get the inexpensive rondovels at EP, there are better values.
Go whenever works best for you. You’ll have a great time.