Two spectacular waterfalls can be accessed easily from HW99: Shannon Falls (close to Squamish) and Brandywine Falls (30km after Squamish). The waters of the Shannon Falls tumble over several cascades and spray quite far. The Brandywine Falls are a few 100m away from the respective parking lot. The name sounds as if you could find some hobbits there. Well, I have not seen any ;-)
The Joffre Lakes provide a good opportunity for a hike (thanks to Ralph and Carsten for the recommendation :-)
At Seton Lake, close to Kamloops, the landscape changes from green land to dry land. Additionally, the tree trunk show a strange blackness - natural or from fire? At Lillooet, I left HW99 and headed for Lytton via HW12. Lytton claims to be the hottest town in British Columbia (regarding temperature, not nightlife). There, I changed on HW1 north following Thompson River until Spences Bridge.
From Spences Brigde, I went via HW8 and 97C to Merrit. On the way to Merrit, the landscape changed again: more and more forsts. From the HW97C to Kelowna you can see endless hilly forests. Shortly after sunset, I finally reached Kelowna.