Before starting, let me tell you that you need minimum two days in order to reach Leh by road. Here is a small collection that you could try if you wanna experience the Himalayas by road.
Srinagar- Leh route
This is perhaps the easiest routes to reach Leh. You can fly to Srinagar and then take a cab.
Reach Srinagar. Spend a few hours around Dal Lake, or at similar spots if you reached there in the morning. Post lunch, take a cab to Sonmarg, one of the best destinations in the Kashmir valley. Takes hardly four hours to reach there. Overnight stay at Sonmarg.
Wake up early in the morning, so that you can experience Sonmarg a bit by foot. By 10 in the morning, take a cab towards Kargil. It is advisable to keep your Aadhar Card handy, as you might require as an Identity proof. En route visit the Kargil War Memorial. Post lunch at the War Memorial, proceed towards the actual Kargil. Takes an hour more.
Today is the last day of your road expedition to Leh. Depart from Kargil as soon as possible because no one can predict the nature's fury on the route. The road had ups and downs and steep curves. These keep you excited throughout. You'll reach Leh after 6 hours. After your Leh trip, you can directly fly from Leh.
This is the safest road route to Leh, the other being the Leh- Manali route. The latter is a bit risky, crossing the Rohtang Pass and also no one can predict the nature's take on you. I hope this will help you in planning your next trip by road to Leh.
Be safe! Stay safe! Trip safe!
Happy trippin'!