I recently returned to my first save, where I was in the position you describe and had given up on that farm as being "done." Which was very much not the case. For starters, it was created and "finished" in v1.3.36 so I had all the v1.4 events to do which was a nice motivator to return.
* I'm married to Penny
so her 14
event inspired me to decorate the house, which I've never done in any save, and that was actually way more fun than I'd anticipated.
* I've added 6 fish ponds for the express purpose of getting materials to fish up all the Legendary fish, I have 3 of the 5 now. I also got the Lava Eel and am trying for the Octopus, the other 2 very difficult fish. I will probably try for the full catch of one of every fish after the Legendarys are done.
* I only got the bachelorettes up to 10
and now am doing the same for the bachelors as I've seen few of their 6
and above scenes.
* I tried to make a maximal Farm setup with 500+ crops to be harvested in a minimum of time and that's quite a task for someone who has spent a lot of time on this forum singing the praises of Lazy Farming. It's going pretty well and the Golden Hoe is a great help here, but it's getting Iridium next.
* I also reorganized the entire farm layout for efficiency and access to:
the new giant Farm
Greenhouse
Barn & Coop and their grazing areas
Shed full of Kegs and Preserves Jars (soon to be Sheds)
Tapping Forest
Fish Ponds
Outdoor storage area
And probably some other stuff, too. Funny how much you can do after you think you're "done."