The country is now open to tourists and it has so much to offer in terms of scenery, historical cities and modern architecture. The locals are very welcoming and there is free movement around the country except to Medina and Mecca, both limited to Muslim worshippers and visitors.
I would recommend seeing the Nabataean tombs in Madain Salih, near Al-Ula, a UNESCO World Heritage Site, followed by a visit and stay in the vast desert area.
In the south you'll find the mountainous and fertile areas of the Saiysad and Aseer, transiting through Tai, Al-Bahah, Abha and Khamis Mushait.
The west coast offers diving opportunities.
The modern cities of Jeddah and Riyadh offer historical sites and dramatic modern architecture.