some good ideas here. You can't really change the past out of game...
Give the players an illusion of choice sometimes makes for the best bet, I think. If the players are at point A and you want them to get to Point D you do not have to have them go through point B first to get there and then to point C. Give them the option of B or C, but then if they choose C first, you can have clues at point C that can lead them back to B.
And, if the players insist on not listening to a talking portrait again, I would make sure that said portrait gets in some choice sentences before it is stashed in a bag of holding (talking is a free action most times...) "Why I have never been treated so rudely before, not even when <important clue to plot hook> happened!"
Also, while you think a naga trapped by narcotic mushrooms is an interesting encounter, not everybody will share your point of view. Some naga are good, some are pure evil. If this is an evil naga, why risk an encounter if it is already trapped? If it was a good naga, there should be a penalty for them not helping to free it.
And, if they continually ignore plot hooks, have them suffer the consequences - have the impossible to beat monster capture them, and tell the players that the key to their freedom was on that parchment in a foreign language... or, have the monster also imprisoning a family member of one of the players and say that unless the PCs retrieve said parchment, the family member will be killed.
Give the players an illusion of choice sometimes makes for the best bet, I think. If the players are at point A and you want them to get to Point D you do not have to have them go through point B first to get there and then to point C. Give them the option of B or C, but then if they choose C first, you can have clues at point C that can lead them back to B.
And, if the players insist on not listening to a talking portrait again, I would make sure that said portrait gets in some choice sentences before it is stashed in a bag of holding (talking is a free action most times...) "Why I have never been treated so rudely before, not even when <important clue to plot hook> happened!"
Also, while you think a naga trapped by narcotic mushrooms is an interesting encounter, not everybody will share your point of view. Some naga are good, some are pure evil. If this is an evil naga, why risk an encounter if it is already trapped? If it was a good naga, there should be a penalty for them not helping to free it.
And, if they continually ignore plot hooks, have them suffer the consequences - have the impossible to beat monster capture them, and tell the players that the key to their freedom was on that parchment in a foreign language... or, have the monster also imprisoning a family member of one of the players and say that unless the PCs retrieve said parchment, the family member will be killed.