I planned on kayaking through some wide canals in the New Hampshire coast, in the marsh land. Any ideas for stuff to troll at that slow of a speed.

What are the regulations? If you can use trebles and barbs I'd try a handful of River2Sea V Joint Minnows

Jigs with grub tails.

For a slow speed troll I'd probably start off with hard jerkbait like a #14 xrap or a Yozuri magnum, something on that order.  I've been very successful using metal jigs like (every company calls them by a different name) speed jig, sling jig, jig fish, crippled herring.  Two companies' metal jigs I like are Braid and Gotcha.  Not only do I troll them, I cast them and jigging them is real hot ticket down here.  Bucktails like a flair hawk work well as they have a longer tail than many bucktail jigs.