Oops...I'd look a bit of an arse if I left for the apocalypse and left the sword here.
As for the canal boat idea...not so sure as I like it. Canals aren't that deep. It'd not take much for a (formerly) human wave to bum-rush the target and just start walking over the bodies of those already killed. And besides, lock gates, got to get out some time/
As for water...whatever the cause of the brain-munching, don't ever drink water from a natural source without boiling it first, there are all kinds of natural nasty microorganisms. Water from static sources is a lot more likely to be the carrier of something less than pleasant, that from mountain streams less likely, either way, if its living, a good long boil will kill it, well barring hyper-thermophilic organisms, but such are adapted to such environments (E.g scalding hot springs in yellowstone, some deep-sea thermal vent inhabitants make their living as the next door neighbor of superheated water hot enough to melt lead, and laden with toxic (to us, to them, its dinner) hydrogen sulfide and other slops from the deep sea)
Anything that adapted to high temperatures is unlikely as hell to be a human pathogen, organisms in extreme environments tend to be specialists.
Anyhow, any water other than collected rain should be filtered first, then boiled. Bits of ground up rock dust can give people the shits, in the case of unfiltered water. And definitely avoid anything with obvious algal scum on top. Thats asking for a nasty surprise, both fresh and salt-water microflora have a nasty habit of producing some rather virulent toxins.