1. I'm pretty sure this one was only post-Chosen, but it was definitely after Spike burned in the Hellmouth. Buffy entered a type of coma/dreamlike state and was reliving her relationship with Spike in S6 inside her head, but with her being more caring and loving so it's become almost like this fantasy life for them that never really happened. I think Angel is the one to mind-walk her to bring her out of it since I think Spike is still incorporeal at the time and that's really all I can recall.
2. The other one is definitely Post-NFA where Buffy finds out Spike is alive right before the big battle in the alley, but she gets there too late to be any help. Afterwards, Gunn, and Angel I think, are the only ones left alive, and Gunn tells Buffy that he saw Spike fall, but she doesn't believe it, knowing he's alive out there somewhere. She gets him to take her back to the precise spot he was fighting in and finds his duster. She goes looking for him and eventually finds him injured and being held captive by Drusilla and dressed in a toy soldier uniform or something of that sort.
If you could point me in the right direction, I would very much appreciate it.
