I was thinking the same as I went through the first post, your not going to hike 200 miles unless you do it regularly. Even the mention of the bicycle, your not going to make it 200 miles unless you are already used to riding that far. People who bike and hike 100 miles have to work up to it. Co-worker of min started riding a couple years ago and does urban exploring by continuting when the city bike paths run out but thats still an easy ride compared to the mountains. He goes out 2-3 times a week and so far has worked up to 37 miles before his legs got too weak to pedal. Same with hiking, even if you did long hikes last summer, if you havent done any yet this year your body isn't going to be in shape, you'll not make it even half way.
Sorry to be a downer and negative but I've had to think about this myself as my family farm is 250 miles away so I've had to think realistic. I've been able to travel 20-25 miles in a day with my family, though they are 3 and 5, older kids can do more. I figure in a true life or death situation I could double that but am still no where near the 200-250 miles needed.
You need to look at ways to bug in at the 200 mile from home location. take work laptop and work from there or have plenty of vacation saved up. Make sure your pay is direct deposit and online banking bill pay setup so you can continue to pay utilities on time if needed. Take extra clothes to have some to change into without needing to do laundry each day. Research all the hotels and motels so you don't overstay your welcome at one. You have researched the plan B detours it sounds like, what about plan c and d and e, how far away is the major 4 lane highway which will be repaired first, can you make a 400-500 mile detour to eventually get home?
Vehicle in good shape, tires, belts, hoses, fluids to make an extended detour if needed, do you have a toolkit packed in case you need it. My parents had to replace a brake caliper in a hotel parking lot whn I was in college, dad always took hit tool box so it wasn't too bad to run to the closest auto parts store and swap it out. I carry tools and a tarp to lay on and old clothes to change into should I need them.