Pan Borneo Highway Sarawak:

Review as of 10 December 2020. Been getting queries on road conditions so here goes.

*Personal driving experience with a small car. Hilux different story.

Kilo Nol: Tg Datu- Sematan

Complete, gorgeous but not dual lane.

Sematan-Lundu: Gravelly, some smooth stretches.

Lundu-Bau: SHIT. Steep drops, gravelly and potholed. Dark at night. Just use Rambungan-Sampadi ferry instead, worth the detour for your car's sake.

Bau-Singai-Batu Kawa (Kuching)
Diversions plenty, but drivable

Kuching:
Stephen Yong - Kota Padawan
Road ok, clear diversion. Flyovers all in various stages of completion. Traffic clogs at Kota Sentosa and 10th Mile.

Kuching-Serian
11th Mile onwards complete, onwards to Serian

Serian: Roads still in the works but looks almost complete except for stretch going uphill/downhill after Ampungan.

Serian Bypass (flyover 1 & 2) both complete! Can zip and go straight out of town.

Simpang Gedong - Pantu Junction

Heaven is a place like this. Both dual lanes complete, but as of now only one side is open. Smooth, no diversions, blissful 120km/hour speed.

Then it starts to get patchy here and there (Balai Ringin, Sg. Tenggang)

Lachau: Bad, uneven, gravel.