It depends on the board.
More importantly it depends on the state of your deck and when you can get the token.
For instance, Teacher often has moments were you want to dump it on whatever will let your draw deck that turn and get Teacher shuffle back in sooner. Say Teacher bottom decks and you draw 2 Rats. Putting +cards on Rats can let you play Rats more safely and shuffle through the deck that turn rather than just dropping +cards on your village and forgetting it. Drawing your deck 3 turns in a row rather than having a busted deck that takes three turns to draw is easily a win. More marginal cases are, of course, harder to pin down; but like with Prince Teacher may merit moving the token. And, of course, it goes without saying if the game is ending soon you should just be dumping that sucker on whatever keeps you afloat until next turn (e.g. 1st Teaching is +action on some terminal draw, 2nd is facing a pileout threat from either mass Soldiers or a few Disciples).
Pathfinding can, likewise, have some situational cases. The most obvious is with Villa. Dumping $8 to draw your purchases and play them immediately can be just insanely powerful. I have never done it, but it is not beyond reasonable outcomes to buy Pathfinding twice in a turn allow for a card explosion from Villa drawing into a stocked discard (e.g. something like Processing a bunch of cards, not having more draw cards to get into the discard, buying Pathfinding and Villa to get to the discard and continue the the turn, then Pathfinding something like Scheme for next turn).
I have seen far too many people add +1 card to whatever makes most since in the long term and ignoring the fact that they might not get a long term. Likewise I seen fewer people add +1 card to whatever is drawn on Teacher's first turn and regretting it.
After all, if you lose a card split 7:3, that maybe should not be your Path target even if Village is better than Smithy in general.
Likewise, maybe Oasis is not that hot, but you have Mine/Capitalism out and can turn it into a a very powerful sifter that you can mass gain quickly.
Ignoring all that, the next question is what do I gain out of +1 card. Yeah it increases your search space, but I would argue that going from 7 to 8 (Avanto) is nowhere near as good as 4 to 5 (i.e. my preferred candidate - Tr), particularly as Avanto rarely has trouble with trashing so both raw draw and draw density are not that important in Avanto decks (I can think of a lot of times when I would skip Pathfinding in an Avanto deck). In general, live draw is better than dead (Village over Smithy), and reliable benefit is worth a hefty premium (e.g. Scheme over most anything else). Effects you cannot get otherwise (e.g. any cantrip on a board with no other net positive draw) can be exceedingly powerful (e.g. Path Pearl diver so you can gain a bunch and then play a copper, silver, and gold along with a Necropolis and two Terminals). Some cards get a lot stronger with more deck knowledge - Band of misfits or Overlord work much better when you can pick your action knowing if the 5th card is going to need a village or can be a more useful cantrip.
Ultimately, you want reliability and just to get the +1 card benefit a lot. Sometimes this makes for weird choices (e.g. Fortress is massively strong on a Prssn board, even if you lose the Fort split). Other times it is trivially easy (e.g. your deck has only one action).
Remember, at the end of the day, getting the +1 card token tends not to happen quickly so be sure to account for how many you have of stuff, how many are playable immediately after you get the token down, how many you will add how quickly to your deck in the coming turns, and how many you may lose from your deck (e.g. Swindler) or your opponent gain (e.g. Jester).