What if every once in a while, for whatever reason, one of those kind and helpful quest-giving nature spirits feels like a change of scenery? Maybe they're tired of having you ferry greetings back and forth and want to be relocated nearer to a friend. Maybe they've never seen the ocean and want to be plopped down on the beach.
Boulder quest-givers temporarily become liftable regardless of their size, and tree quest-givers give you a magic seed/cone/fruit that will immediately grow them at full size when planted where they asked.
Set down [X] near the given location. (indicated via marker, with a radius of acceptable tiles)
Plant [X] by a riverside.
Set down [X] near a [localized resource].
Plant [X] near [other quest-giver].
Set down [X] in [Neighboring Thingwall] Province.
Set down [X] in a cave/on the surface. (depending on if they were on the surface or underground to begin with)
I'm tired because it's almost 5 AM where I am and I'm feeling bad for boulders who can't walk.