I don't want to dampen anyone's enthusiasm for getting off the trail but I think a reality check might improve your chances of success.
First off walking in the woods with your day pack and always knowing where you are can be fun.
Bushwhacking a canoe and full complement of tripping gear is not fun it is damn hard work. Try not to have timeline goals. Take what the terrain will allow. A one mile bushwhack could take well over 4 hours. That could be 4 hours of some of the hardest work you've ever done on a canoe trip. Take at least twice as much water as you think you will need in a worst case scenario.
Be aware that whatever your practical load limits are for portaging you would be wise to reduce those limits by at least 25%. I know plenty of excellent canoe trippers who can easily manage 100lb loads on any portages in Quetico. I have not met the man yet that can handle 100 lb loads safely and comfortably off the trail for any significant distance.
Be prepared for the going to be really tough at times and do try to stay found all of the time. Getting turned around for any length of time can really crank up the anxiety level when your hot, perhaps a little dehydrated and fatigued. Be aware that if you get to that state you are apt to make that stupid decision that could be a game changer. That is when its time to slow down and become super methodical in your thinking and decision making. Remind yourself that there is no need to rush.
The real fun of the bushwhack is looking back on how awful it got and how you managed to get yourself through it.