Also consider a camping “mattress” for some cushioning, such as:
A closed cell foam pad (6 foot long, about 2 foot wide, and maybe 1/2 to 3/4 inch thick — bulky, but light and easy to use),
Self inflating bed pad (some of which apparently require pumping to top them off),
Air mattress (requires the most work each night, but is also the most comfy).
The latter two might get a leak, so bring a patch or two, or strong tape.
Consider rain and/or very heavy dew, and maybe no good way to dry cloth.
Along that line of thought, put stuff inside sealed plastic bags, and try for at least good water resistance in your duffle bag — water *proof* is better, but can be expensive.
I found a couple of water proof roll top, 55 liter (14.5 gallon, 33″ x 8″ cylinder) capacity dry bags near the kayak section at a sporting goods store for $40 each. At another, I could have paid over $100 more for one duffle bag of about the same total capacity that was only water resistant.
It was similar pricing for bed pads/mats — so check the details in more than one place, whether online or in person.