Lanefan
Victoria Rules
Yet still two resolutions, notwithstanding. In this case the DM resolved the first, the die roll resolved the second.Not necessarily. The rule is not "if climb, then roll Athletics" or "if search for clue, then roll Investigation." If it was, then yeah, you're going to have to break that out into distinct ability checks to resolve the action declaration.
The DM can instead say that climbing the tree is trivially easy, thus making the outcome certain and thus there is no ability check to resolve climbing the tree. The DM may then say the clue is hidden, making finding it uncertain, and call for an ability check. One action declaration, one roll resolves.
Again, two resolutions, only this time the roll-DM sequence is reversed.Alternatively, the DM can say that climbing the tree is hard, perhaps because it is slippery, but that once up in the tree's canopy, the clue is easy to see. So here the DM just calls for the Strength (Athletics) check to climb and, if successful, the PC gets to the canopy safely and the clue is there to be found. In this case, the clue is just part of describing the environment after narrating the successful climb.
And what if the clue isn't there at all - the character's climbed the wrong tree, or the mysterious "third branch to the left on the side of sunrise" referred to in the prophecy was actually talking about a river and the PCs blew the call?