If you only want to do a couple of hours, heading up the track from Annat to the Loch an Eoin for a look around and back down is an excellent ride. You get great views and one of the classic descents.
For a good day out, there are loads of options but it depends on fitness and how much hike-a-bike and gnarr you want. Two of my favourites are:
For big day out the “lollipop” route (Annat > Beallach na Lice > Coire Grannda > Achnaschellach > Bellach na Lice) is just amazing but is tough. There are easier variations, like taking the track through Coullin Forest and back over the Beallach na Lice.
I really enjoy the out and back ride from Kenmore to Applecross. It’s no overly techy but just nice trails and great views. There are good cafes / pubs in Applecross. Just a nice day out on the bike.