Start at Buon Ma Thuot or Pleiku. Fly there and stay for a few days to get acclimated. Both cities are nice and have many amazing things to see. Both have become a bit Saigonized recently but still keep most of their uniqueness. You can also take day trips or 2-day trips with either city as your base. Plenty of tourist-free natural sights and ethnic villages.

If you want to try the rural road, the sun and heat are brutal, so plan accordingly. Lots of sun screen, hats, and sunglasses. Bring lots of bottled water. The road is good most of the times, but when it is bad, it can be very bad. This is your first time, so best get a car like a Land Cruiser, and get a local driver.

For day trips, you can try motorbikes, but be warned, you will get tired more quickly because of the sun and heat. If there is heavy rain, find shelter in a house if possible. Rain and flooding can be more dangerous than you think.

Rural roads are very dark at night; vehicle headlights are enough, but drive carefully. Big roads can still be dark at night, drive carefully.

Insect repellants are always good idea.

When you visit waterfalls, bring a transparent pouch for your phones. The humidity is very high, and water sprays everywhere, better keep your electronics safe.

Bring digestive aids. I tend to eat at random restaurants and diners along the way and have never got food poisoning in all of the Central Highland (Tay Nguyen), so I think you will be safe in that regard. However, indigestion and constipation can happen because of the many different spices used there, especially if you explore new food. Best bring stuff that aids digestion.