I've just started a new game. At the beginning, I'll often pick the farmer up after fish have been delivered to the food bin and drop him or her back in the ocean. I figure that it saves the little bit of time spent walking all the way there. Hopefully, the food stocks will increase slightly faster and the farmer will become an adept a little quicker.

Sake stands and waits for me to pick her up. She spends much longer standing by the bin than most farmers I've seen. I realise they often take a little while deciding what they are going to do next: fish, collect coconuts, or harvest the crops/water the field; perhaps goof off. Sake, though, has no real choice to make; the only food she can gather is fish at the moment. I'm sure she is just lazy and wants me to save her the walk!

She dislikes heights, so I'd have tought, if anything, she'd prefer to stay safely on the ground!

I had villager adept farmer who dislikes swimming and turnups. He water the crops then keeps running away. I don't think he well go farther than adept he was 31.

I've had that happen to me as well ... thought they were exercising, found out they were running away. Easiest thing ... give'm something else to do that they WILL like and they can become masters at ... funny thing though ... had a master healer who didn't like medicine .... but yet, the life meter was full up most of his life ... go figure!!

Yes, I always "help them out" at the beginning of a game. They're way to slow, & they do stand around in a daze at their bad luck. At that point in the game there really isn't anything else usefull to train them in, so I don't give them a choice.
About the fears tho, (that villager who's afraid of heights wont gather coconuts for you) I've noticed that they wont fish/garden or whatever when you try to make them, but if you have them set to farming & train them with the area they're not afraid of, they will fish/garden on their own most of the time, and can get to Master level.