Tony – first rule is reduce weight of what you are packing. If you take lots of stuff then no matter where you carry it it will feel like lead.
Earlier today I just happened to look at an old spreadsheet of mine comparing what I carried on the first two editions of the YD300. In 2015 I had 10kgs of bags, kit, food, etc. the following year I had 5.5kgs. That’s a big difference in what I’m hefting around. My 2017 kit was 3.5kgs so even better. In all cases the kit was on the bike.
On the 2016 BB200 I used a Camelbak because there weren’t many reliable, clean water sources. So probably 50/50 in terms of bike to me.
As Colin says: decent bags don’t bounce around.