Ok, so to elaborate on my above post.. this is the current strategy I'm employing:
As the first dungeon to be conqoured by yours truley, as well as being closest to your characters home, the Green Ruins doubles more than suitably as your farm away from farm. The layout of the ruins (a giant, multilayered donut of doom) makes it easy to navigate, and after a few trips around you'll know it like the back of your hand. Obviously, having a silver hammer helps to reach the few rooms or paths blocked off by the small brownish boulders, but the real key here is to have a monster for transportation. My favorite pick is [default name]Silver, the wolf monster towards the end of the Whale Island Fin.
With some sorta transport monster available, farming the Green Ruins is SO much simpler, trust me on that. Not only can you access more ground on your four legged friend, but while you're watering or harvesting your crops, it'll keep those pesky native monsters off your back.
With that said, even I don't have this dungeon 100% tilled/farmed and its probably best that way. I do have the whole first floor growing though, but only certain segments of the 2nd/3rd floors, making sure to keep some of the soil as is in order to harvest the wild grass and lumber (though rocks and weeds are pointless, so its 50/50 you'll get what you want there).
I'll go into detail here on my usual routine for my trips to the Green Ruins:
As stated once before, the first two patches of soil are growing cucumbers (take too fucking long) and strawberries. After going thru the vines, and pay a visit to that one big patch of land (i believe its the biggest in the dungeon) where I have the top row growing turnips* and the bottom growing strawberries.
Move north passed the room with the boulders and head to the one long room with 3 sections of soil, each with 2 of the 3x3 patches each. Here i have crops growing in this order (from left to right and top/bottom:
Turnip/cucumber, Cucumber/Cucumber, Turnip Cucumber
The next room to the right I decided to use the 4 patches of soil there for grass**. I go back to the last room, head down past the vine and work my way to the far right. I go into the first room on the right, where i have more grass going, head downstairs where i have strawberries, then head out and to the left. Depending on whether or not i've harvested crops/wasted time I either go left passed the door to the shortcut stairs, or just head down the the 3bf. If i do go left past the door, i go down into the first room where i have Strawberries/turnips, then to the attached room where i have more grass. If i go down to the 3bf I hit up the first room on the right where I have more Strawberry/turnip combos growing. The last floor only houses turnips, which I might switch out for grass soon..
And so ends my routine trips thru the Green Ruins. If I go there first starting fresh at 6am I can be done by 11am on a good day, giving me plenty of times to work on the Lava ruins, though since I have plenty going on in the Green Ruins i'm thinking about giving up both every other day just to finally get my ass into the Snow Ruins and hopefully beat that bosses ass before the end of Winter.
*Turnips are awesome in the Green Ruins (and Whale Island) when you use them merely to grow Runes. 4 days of watering and you just leave em unpicked so you can get a new Rune everyday, it helps out a ton when dungeon crawling.
**Grass: I've been using grass as a more productive turnip. Harvesting crops in the deeper parts of dungeons seems like a time waster, so a 5 day investment to grow grass produces the runes you'll need to regain RP by the time you get to those rooms later in your dungeon crawling as well as letting you harvest fodder every 2 days. Obviously you'll want to be sure you have a special attack available for both your watering can and sickle before attempting any of this though, since that alone will be your biggest time saver.