The scenario as i understand it is getting 200 miles home from roughly the point one or more bridges or tunnels make the route you drove in impossible. Further, as I understand it, ours no to question why but to suggest how to get home.

So, I would do the STOP thing. The theoretically possible ways to travel are by land, water, or air.

Land:

Perhaps your vehicle is rugged enough to exploit jeep trails, old wagon trails, intact railroad lines, and some cross-country. You may be able to stitch together a reasonable route if you carry detailed maps and have spent time evaluating each link in your intended path.

You will need to carry a lot of fuel, spares, repair tools, etcetera. You will need to plan for a lot of walking if the route proves impossible, the vehicle breaks down irrepairably, etcetera.

Perhaps you can tow one or more ATVs, that should have a greater chance of making an overland journey of this type. The same supply considerations apply.

If you have to walk with a family all or a substantial part of 200 miles in rugged territory, it will take you at least several weeks and likely a couple months. Living off the land will be required. Les, Jac, and others have made gear suggestions. I would suggest adding a lot of snares, a few gill and throw fish nets, a couple of collapsible crawdad traps, and a lot of fish hooks and line. You will need some rope and some climbing gear to get past / over landscape obstacles, with the addition of something that floats people and gear to get past / down water obstacles.

Water.

Following the river seems the most likely way to travel 200 miles with family, even if you mostly walk the banks. If you have a large, whitewater raft designed to travel this kind of river, I would seriously consider using it - even if you have to "line it" downstream along the side of the river much of the time. Gear suggestions remain the same.

Air.

Apparently the ultralights or pocket blimp are out.