6N in Kyushu Itineary

Hello, would like advice on how to plan our Kyushu trip, it�fs our first time to Kyushu and we are planning to drive.

Day 1 to Day 4- Rent car from Fukuoka and head towards either Beppu or Yufuin to stay for 3-4 Nights. Plan to visit USA Safari and the Hells of Beppu.

As we are travelling with 2 young kids, any other places that we can visit around the area that�fs an easy drive away.

Any ryokans to recommend that are welcoming of kids (1 years and 4 years), our budget is approx US$400 to US$700 a night.

Day 5-7: Drive back to Fukuoka and to stay for 2 to 3 nights.

Thank you

First, I think you mean the African Safari in Usa City, is that right?
http://www.africansafari.co.jp
You need a car for that obviously, but you don't need to drive to Oita just for that - just get a car for a day in Beppu and use it for the safari. But if you actually want to travel, then the car can be useful - if you go to the Aso area, there are many great places only with access with the car or bus - Kurokawa hot springs might be right up your alley if you want to try it. There are some great places in the area - the Daikanbo Lookout, for the Nabagataki Waterfall.
https://youtu.be/fqNCq1kMdac
There is the Aso volcano as well, of course. You don't say when you're traveling, but if after winter, the Kuju Flower Park is very nice.
http://www.hanakoen.com
If you plan to use the expressways a lot going all over, then an expressway pass might be a good idea.
https://global.w-nexco.co.jp/en/kep/

Depends on you interests.

Bungo Mori has a small rail museum,a preserved steam loco. Ride on miniture rail on sunday mornings

Takachiho gorge

Asosan

Kufu mountains for walks

One place I just visited a couple of days ago which is very kid friendly is the Yukai Resort in Ureshino. Due to Kyushu's small size: Huis Ten Bosch, Nagasaki and Mt Unzen are easy day trips. Nagasaki is probably my favorite city in Kyushu - with plenty to do.

What exactly do you want to see and do?

If you are only traveling to Beppu with a car - then hiring a car for a day there as suggested might be a better idea. If you want to drive around more - then a hire car does make it easy but check that the car you hire can hold 2 baby seats and that you book them as well (might cause problems with luggage storage and parking as well)

How about taking that trip with a camping car? Kyushu is just perfect for that.
Plus it gives a lot of freedom in your schedule..not having to check in/check out etc.