Advice, tips on a month long journey into BC, Canada?

The most well known long trail in BC is the Great Divide Trail following the Canadian Rockies from Waterton Lakes NP(near the US border)to Jasper.There would be resupply opportunities every 4-7 days so you would not need to live off the land per se(which would certainly slow you down)rather carry a backpacking stove and fuel to prepare freeze dried or other compact meals.The better shape you are in the easier and more enjoyable the hike is likely to be but people start long trails out of shape all the time and use the hike to get in shape.I would recommend continuing the exercise you are doing plus add weight training as well as hiking with a backpack(for activity specific training).All these are good life long habits and the more you can do the better.Perhaps, do a few shorter overnight or longer backpacking trips as a shakeout.And,stick around these forums and ask questions in the gear,cooking and Trailhead Register(for general questions)forums.

If you are talking about something more remote where you are doing more hunting ,fishing,scavenging ,whatever for food I am sure there are plenty of opportunities but someone more knowledgeable about the BC wilderness than I would have to answer that...

Not to kill the dream, but this is a very ambitious plan for a first-time backpacking experience. Several parts of the message don't quite match up:
No packing experience (so no gear?), a dream to "live off the land" but no real idea of what BC is like (asking where you should start and end?) so maybe you think BC is all wilderness and you just kill something for dinner? No mention of when this trip might happen? Remember that the west coast of BC is rainy. When I started reading your message I thought of the LifeSaving Trail —oops! The name has changed since I lived in Seattle. Now it's the West Coast Trail, a pretty grand name for a trail that is just on the west coast of Vancouver Island, and only half of that!

That trail was established many years ago to give shipwreck survivors a shot at finding their way to civilization,…if they first could to get to the shore. The Straits of Juan de Fuca and storms sent plenty of vessels to the bottom. But now, seeing the webpage linked above, I see the mention of "comfort rooms" and ":1000 people a year hike the trail!" And yet, maybe it's a viable way to test your dream with less chance of regretting your plans? It is a hard trail but can be managed by most. It is only a week of travel, but oh what a week it would be. Hiking mostly beach and watching tides, waves, rain, slick rocks; crossing a river, climbing "stairs" to clifftops, and camping in wet conditions. Living off the land? Sure. Assuming you like seafood, you can forage clams and mussels, even kelp. Berries? Probably (time of year matters) and probably bracken ferns and other items can be found. Eat all you want.

Transportation would be available (fly to Vancouver, ferry to Victoria), so hike it R/T and get three weeks of experience, lots of photos and stories, and end back in Victoria with tea and a scone at the Empress Hotel (after you have showered!)

You should add some info on when this trip would be scheduled? Is BC a primary goal for some reason? It's a beautiful area and has excellent sources for enjoying some of the culture of the PNW Coast Indians (fantastic artwork and history) if that interests you.

A trip like that would be the culmination of a ten year plan, or longer. Gain skills first with shorter trips, building up experience and knowledge. You may find it is not as fun as you think it will be. The longest I was out solo off trail was 6 weeks and would not want to do it again.

BC is not just a bigger version of the lower 48. Depending where you go there is no government rescue to save you if you have an accident. A friend recently spent three weeks in Wood Buffalo NP in Alberta (larger than 5 Yellowstones and virtually no trail system). He said the most sobering part of the trip was the realization that any injury could be fatal -- bad cut, broken ankle, et al. Even with a sat phone rescue would be 2-3 days or longer.

Remember the mountain man stories of Jim Bridger and Coulter? If that is what put the idea in your ahead the trip would be a romantic adventure, remember the mountain men trappers had a 25% annual fatality rate. 1 out of 4 did not survive a year.