Her path is for Trump to be ineligible, incarcerated, or interred. Every one of those outcomes is possible, if unlikely. But if that happens, she ends up being the only other Republican with any delegates at all.
Why would that be difficult? I'm sure the prison will get used to letting in all sorts of people. World leaders, various grifters of the week, ambassadors, etc. Not that it'll ever happen, the SC will say he can pardon himself. That's why he put them in after all.