Try doing some sums, WWW:
Even a max fuel wt Vulcan only carried 88000 lb of fuel. It burned around 10000lb in the first hour, then 7-8000 for the remainder. It did 500-ish KTAS at high level, around 360 at low level. Fairly obviously the route East wouldn't be a straight line, so have a guess at a route to a fairly obvious location in the old Sovietski Soyuz, including a descent to low level to avoid radar. Measure the distance, work out the time and then see how much fuel that leaves you with......