Here's an idea: take a walk in the snow

[SimpleFarmer]

Bored during those Long Winter days with nothing to do? Are you torn between fast forwarding through the beautiful winter landscape or walking around and viewing the beautiful countryside?
Look no further: Collectibles.
Take a walk in the snow; through the parks, under the bridges, and up on the elevators. In just a half hour, you can find 10,000 worth of collectibles. In a game where $1,000 is becoming more and more difficult to come up with, searching for these collectibles has become a worthwhile endeavor.
I spent December January and February on 10x walking around the map and delivering my lettuce and other crops and found 33,000 worth of collectibles.

[SimpleFarmer]

Update: this is much more fun with a horse, but a lot of the collectables are in places you can't get to with a horse so he sometimes might wander back to the stable while your up on the grain elevator