One of the things that came to my mind recently about where Russia can be helpful is a potential agreement to operate PLAN SSBNs in Russian waters. As an example, the JL-2A supposedly has a range of 11,200 km. That's sufficient to hit a very large chunk of the US from the Bohai Sea - it only leaves around 20% of the US uncovered. However, from there it falls just short of hitting Washington, DC, but it gets so close that I'm struck by the suspicion that the "11,200 km" number was cooked up specifically to achieve that effect.
It seems reasonable to me that the number could well be at least 12,000 km, since missile range improves dramatically with better propellants and motors. Once you pass a certain range threshold, it's incrementally easier to add to the range of the missile just by how the physics works.
Whatever the case, if launched from north of the Bohai Sea (e.g. the Sea of Okhotsk) the JL-2A can cover the entire US and then some.