agreed, tough to get one in the bed but over the top and hanging out the back a few feet, maybe....we (myself, wife, 2 elementary school age sons, labrador retriever) used to fish and weekend camp out of a 17' Alumicraft canoe, with a trolling motor and sonar, in large N. Idaho lakes (Priest, Pend Oreille, Coeur d'Alene, and lakes in Glacier NP), but you can't toss a long boat like that in a truck bed (It rode on top of a minivan real good).
you could go with 2 inflatable kayaks and put an adult and kid in each, these are good ones with a rigid floor:
Aquaglide Chinook XP Tandem XL Inflatable Kayak | Next Adventure
CHINOOK 120 XL
it would be easy to connect 2 of these sort of kayaks together side-by-side to make a super stable raft with 1100# weight capacity and have an easy place at the back between them to mount an electric trolling motor: