No, we had our own cars on both trips. Therefore we did our own driving inside the park. Personally we did not see any value of the safari drives done by the various services / resorts. They go to the SAME places any of us self-drive folks go if it is inside the public areas of Kruger. They do NOT have some secret spots. They rely on their walkie talkie to communicate to each other (regardless of companies) on where something is spotted. Meantime you are on the safari car with other people AND no air conditioning due to the set up that the seating area is not enclosed. Most safari drives use either Jeep or Toyota modified SUVs with complete open top. We much prefer the airconditioned environment in a private car. Toyota Corolla is very popular rental car type in South Africa. We have rented from Avis at least 5 times in 3 trips, they are all Corolla. We took it to Mountain Zebra NP, Addo Elephants NP and Kruger NP - no problem at all. The big camps all have gas stations. One has a car wash facility where we used it each time on the last day - needed that else you would be charged cleaning fee at return - cars would become Very Dirty after even just a day in Kruger.

On N4 there is a big facility with the usual restaurants, gas pumps AND a little zoo with the exotic animals found in the park. You could have the car wash there too.

I found this site quite useful for planning the visit.

Johannesburg International Airport to Kruger National Park Drive

The private reserves have their own little areas that are adjacent to Kruger but not part of the NP, and without any barrier - they can then drive in those areas at early morning or late evening hours. But as far as Kruger NP itself - where they go you can go just as well and often you are better off due to you dont have a schedule to keep and you dont need to please others, like the fellow customers on the same safari drive.

The Kruger camps have safari drives one can book if staying at the camp. The morning drive probably is better value as you leave in the dark and then return after sun rises, versus the evening drive basically is in the dark shortly after you are out and about.
However from what I have read from different sites on people's trip reports, it really is not worth the money to have "guided" game drives.

In 2016's trip we passed a spot under trees fairly close to road side, where a pair of lions were resting with the male got up to mate several times while the lioness could not care less but continued her afternoon nap. It was fairly comical to be honest! We first spotted a couple private cars stopped by the road side and then we saw what they saw. Until we left we did not see any game drive car passed by. On another occasion we passed an area where someone at the camp told us they saw 6 lioness the day before. Sure enough we saw a group of lioness scattered around, all having naps and occasionally turned over. Not even a passing car stopped when we were watching quietly. Then one day at lunch at Lower Sabi Camp when I checked the board of sightings (yesterday and today), a couple told us they just came back from watching a leopard caught a kill then finishing it on the tree. They said the kill was pretty good size so the leopard probably was still eating. So we skipped our lunch and headed towards the direction, the sighting was about 2 to 3 kms in a side dirt road. When we arrived there were like 1/2 doz private cars and 2 safari drive cars were there watching. The safari drive cars had to leave as well as a couple private cars. We then were able to get into a spot that was very close to one side of the tree with a great angle of the leopard resting on the branch - yeah, it had finished its feast and resting now. Then the best high lights were 2 sightings of wild dogs which are supposedly very rare considering you are encouraged to report the exact locations of the sightings so the park could keep a tab on them.
One was a family with pulps. Again only a few private cars were watching quietly. The other time was when we were on our way towards the gate to leave the park near closing time - there were almost a doz of them wondering across the road and scattering on both sides of the road. It was due to that sighting when we finally left we drove at a slow pace - there was speed guns right at the road side just out of Skukuza camp, on the direction leading to Kruger gate - multiple cars were caught but we were fine - the lady cop waved us to pass...

In 2017 the high light was when we watched a leopard feasting on its kill on a tree - the whole process... In the morning we passed a place where my husband spotted a kill was hanging high up on the branch. We waited a while in hope to see the leopard. No luck. We moved on. In the afternoon on our way out we made a point to check the same area again - there it was, just started feasting. Then I saw a hyena was waiting at the bottom of the tree for droppings. Then another hyena came, and the first one drove the second one away. The second one seemed to have suffered some wound in the past and was cripple. It did not leave far but quietly wait... The whole thing was surreal. There was not a single safari drive passed by the whole time.
Also watched huge herds of Cape Buffalo, like over 200 of them, resting and wondering along the bank of Sabi river. Big herds of Giraffe and again elephants on the other side of Sabi River right across from the restaurant at Lower Sabi camp. Rhinos by the road side no more than 4 to 5 feet away...
Basically it is a lot more freedom and fun doing the drive yourself. South Africa is probably the ONLY country that allows one to do self-drive on a safari trip. I would take advantage of that.

An FTer who posted often on various forum, went in Spring of 2017 - he showed me a pix of a lion family - 3 lioness and a few cubs, spotted right when he turned into a dirt road just after entering Malelane gate. He was the only car there the whole time until the lion family got up and walked into the bushes. So on our return trip, also entering from Malelane gate this time as we came up from KZN, we went to check that little dirt road out (it was a loop) - no lion but we saw a dejected hyena walked towards us that it passed the side of the car soooo close that I felt I could pat its head... also a pair of Cape Buffalo just staring at us at close up...

You would have a lot more fun doing the drive yourself. It is very easy. We did not venture into the dirt road much in 2016 due to the road conditions were very poor because of prolong drought. But in 2017 driving on the dirt roads was much easier after Kruger received lots of rain in Nov 2016 and the Park was able to do some road maintenance / improvement. The Corolla handled it just fine. Be sure to buy the detailed Kruger "map" that is more like a magazine style book - it has the details information on the roads both main, paved ones and the dirt, unpaved ones. It also gives description on each "zone" inside the park, and explanation on the animals you would have a chance to see in each "zone". The book is available at the gate entrance.

Finally while Kruger is fun to visit, after 2 consecutive years we now would take a break, and look into Tanzania instead.