On the second, if you mean the one where you have to find a spot for you and Darkness to train, go to the building by the bathhouse (where you drill the hole to spy on the girls). At the back of that, there's a door leading to a backyard kind of area you can clean up for the training area.
Edit: On the gift for grandpa, you pick up the package at the bathhouse, and then go to the old dude north of the entrance to the dungeon. You'll know you're in the right spot when suddenly bees everywhere.
Though speaking of...I finished that mission (and the ones that show up at the same time). I see no more missions on the board, and I swear I've been all around town. The only thing that seemed to have any more content is that I could get Darkness to do the crunches faster by telling her she's doing it wrong, but that's only once per in-game day, and I don't see any way to advance time now (except buying rounds of drinks, and that would get very expensive without a way to make further money). I don't think I've reached the end of current content, right? The tags state there's futa/trans in this, but I have yet to see it.