Sea Cans are not a bad idea except, in my opinion you would be committed to one location. if something were to happen and you would have to leave your bunker, you would be hooped! all your prepping and planning would be wasted, and you would be up shit creek without a paddle. Assuming any vehicle that you would have had up top will be stripped, stolen or even inhabited by someone else means that you are on foot, with a reduced ability to pack stuff with you for a new start someplace else.

What are you're thoughts on this people?

From my understanding of how emp and nuclear radiation blas goes. I think it is possible to have your vehicle in your bunker in something like a tunnel with wall that have sharp edges to bounce the waves oncoming from nuclear blast or radiation. A blast door would also help. Having a plan to take back your BoB must be pre planned so you dont lose your hard work.