A head torch is a good idea, though not strictly necessary.
The OP suggested that they wouldn't be doing any cooking. Though I have to admit, I'd take my stove just to have coffee first thing in the morning. the one time I didn't take it, I regretted it for that reason.
Tigerbiten wrote:An extra 10 Kg in weight will slow you down by roughly 1 mph on gently rolling terrain.
So I recon a full camping load will slow you down by around 2 mph on average, 1 mph if very flat and 4 mph if very hilly.
Using that you should be able to roughly work out how long you'll be on the bike each day.
I don't think that works for me. In relatively flat bits of the UK, I am about 3 mph slower loaded (15ish kg) than not. On hilly terrain, I am about 5 mph slower loaded, than not.