Wow, I enjoyed reading all your replies. It's true that there are many options. I like the tuna in foil pouches idea, along with some crackers perhaps.
So, for breakfast : plain room-temperature bagels + peanut butter, oatmeal (boiling water).
...and for lunches : CLIF bars, tuna+crackers, Lipton soups and assorted freeze dried meals (boiling water). Going to sample a few of those!
I will have access to the camp's propane stove, however I might take my MSR Windpro just for kicks, again doing my cooking whenever I want to.
Drinking water won't be available. Two options then : either I take 4 x 4 liters of water and some Gatorade powder. Or I could succumb to the Katadyn Vario water filter i've been eyeing for a while. It would be my first filter and I must say that on paper, the specs look very good. Slightly pricey, but I presume it's a quality unit. I will be on fresh water indeed, fishing on large lakes. I know that those filters come with tubing so that the tip sinks in the water, to a depth adjustable by the user. Would that be enough to avoid getting engine fuel/oil in the filter? Does it appears to be worth getting this filter in order to avoid bringing 12+ extra liters of water? Hmmmm...
I only need to play 5 breakfasts and 5 lunches, so it's not such a big deal at the end of the day.
Thanks!
Bee