I've got a bike, I've got kit and I've got bags to put it in. Just need a spot of help putting it all together.

I've got a Whyte 529er with the usual set of flat bars, 10x3 gears on cable shifters and hydraulic disc brakes. Rear cable and hose running through the frame. The coming off the handlebars, the cables and hoses are creating a bit of a nest which is impeding the placement of a handlebar bag.

Before I get all excited and cram stuff out of the way, is there anything I should be wary of, particularly around the hydraulic hoses. I don't want to load myself up at the expense of being able to change gear or come to a stop.

I just ram my cables back towards the head tube. Never had any meaningful problems so far (sometimes one of the cables catches on an attachment point on the bag, but it's easily fixed).

"ram my cables back" - same here. Never bothered with one of those nice harnesses and no probs.

I used to 'ram the cables back until I had chafe on one of the hoses and had to replace so I had new hoses made to fit around the outside of the handlebar set up.

My setup is a bit of a faff to start with, but involves just weaving hoses in front of and behind the straps and buckles of my bar harness. I try to minimise any bends in the hoses and gear cable, but in general it really is just shoving them out of the way.

I use flexible v-brake noodles at the shifter end, they give a good bit of flex and strain relief without the bend radius getting too small.
Also works great for the Rohloff shifter's stupid perpendicular cable exits. It looks ridiculous on a Mary bar without them!

https://www.amazon.co.uk/Acor-Adjustabl ... B001DHLOA4