I have a Trangia stove with meths burner and also the Gas adapter.
It's quite an investment but, with the non-stick bowls, I'm covered for most trips.
Gas is super convenient and quick to boil water but using meths is a more relaxing way of cooking (and the bottles make you look super hadcore).
I use front & rear panniers and find my bike handles much better for it.
I think a bar bag is essential.
Put a coloured zip tie around the handle of one front and one rear pannier and force yourself to use the same panniers for the same things every day.
Example - Your clothes go in the front pannier with the Zip tie & your cooking stuff goes in the front pannier without the Zip tie. Small things like that make life so much easier.
My tent goes in a dry-bag on the rack, between the panniers. If it's been raining then I'll just put (dry) inner in there and the outer can go underneath, rolled up.
Self-inflating sleep mat of course. Never be tempted by closed cell foam. I went for a big and thick version (Alpkit) because nothing is worse than lying awake wishing you hadn't skimped on a sleep mat.
I use plastic picnic plates, they cost peanuts.
- Sharp (small) cooking knife with blade cover (about £3 from supermarkets, usually high viz colours)
- A tent with a porch for your (wet) gear makes life easier.
I have a Vango Spirit and I can just throw everything in the porch.
CROCS sandals. Yes I know they aren't trendy but they don't weigh anything and they are super comfy, waterproof..etc. Lash them to the outside of a pannier.
A lightweight Tarp.
Look under the tent dry-bag on the rack and you'll see a 6x4 tarp
That's the best £2 I ever spent.
Get them from here
UK TARPS. They weigh nothing, fold up to nothing but make life easier (ground sheet on wet grass, an extra roof with a bit of para-cord).
Here are some Faccombes relaxing on the tarps in France.
3 or 4 luggage straps, the ones with a spring-loaded buckle/clamp about 3cm wide. You can pile stuff on the rack an cinch it all up with them.
Oh yes, a Toe-strap. Put it around your front brake lever and tighten it up.
Look closely..
There's actually not that much in my panniers and I'm sure I could cram it into two rear ones. However, my bar bag and left-side front pannier contain everything I need for a ferry crossing so I know to just grab those two. Distributed load makes the bike handle like it's on rails, lovely.