I take glucose monitor, finger pricker, little bags of haribo, occasionally I'll take a little sachet of peanut butter. I also take my cgm. I try to run with no active insulin on board and I will take on uncovered carbs before setting off for a long run. Personally I'd be careful about "carving up loads" pre run, because I find it really difficult to run when high - running through treacle. So I try to set off when I'm 6-8 and rising, then the run will level off the rise and I'll probably get round before it drops but I've got everything I need just in case. It all fits in pockets at the moment, or running belt when it's warmer.