Yuh huh.
And where would you fuel up? Oopsie.
Not to mention, if you're the last one on earth there are presumably no roads left anyway.
Why would the roads be gone?
Why would you (or anyone) be the last person on earth? Mega-war, that's why. Those roads would have been blown up by one military and used to death by the other.
No one said anything about a "mega war"......lol
Why else would anyone be the last person on earth? Think about it.
Since we're talking pure fantasy you might have been the only person immune to a worldwide pandemic.
Thats as believable as everyone on the planet dying in a war.
If there's a worldwide pandemic, I guarantee you ain't the last one alive. And even if you were you'd be in no condition to make this grand continental trip in a stolen vehicle you can't fuel to drive on roads that aren't there.