I've spent the odd comfortable summer evening sleeping under a hedge, but as I'd been to the pub first I guess it doesn't count?

Hello All, I'm new to mtb bikepacking, looking forward to BearBones200... :) What do I need? I have a bike, Cannondale Trail 29er I've got bivi bag, sleeping bag, tarp etc... I've got a pair of outlier panniers, and an old rear rack at home...but a lot of you guys seem to be running a lighter set up...