There are so many options in the area of the Okanagan Valley & the Monashee Mountains (nearby) for hiking! The Okanagan itself hosts lots of trails from beginner to advanced to keep most people busy. Kelowna itself has a wide range of trails, as well as Vernon, which is situated very close to the Monashee Mountains, which hosts tons of options; from moderate hikes to full-on multi-day adventures. Included here is a link to a very nice site steering you in the right direction. A good backcountry map of the area is also recommended, seeing how most trails involve travel along rough backcountry roads. If you are in the Vernon area, Bluenose Mtn. & Dennison Lake Trail are definitley highly recommended! Have a fun adventure!
Link: Okanagan Area Hiking Guide