I'm considering doing at least one 100% run of this game. But after doing the math it seems a total of 1,480 doves will be needed to buy all the fruit and items. I don't really see a good place to farm these other than off the first boss but the max you can hold at once is 255. There are several shortcuts as well as the railroad to quickly travel across the world so routing it could be interesting.

I noticed that there are several areas in the shipyard that seem to just give you vials as long as you are in the area. I'm not sure why? I looked for areas that possibly could give doves like this too but didn't find any. It doesn't seem like a glitch but who knows. Maybe somewhere it's hinted at by an npc.

Edit: Seems there's a secret room in the Lost at Sea region that gives full doves/vials. But it can only be used once.

Here is an initial route I made.

Also weirdly enough in the Genesis version, I discovered that unlocking the door for the Lost at Sea secret room marks the pear room in the Shipyard area as empty so it becomes unobtainable if not gathered before going into the secret room.

I think it does this in nes version as well. In my 100% run I didn't actually get the 6th pear because it wasn't there... I assume it was counted because I visited the shop and it was a game error not mine