If you are planning on getting your total up, I would first suggest raise your slayer to ~90, while training your attack and strength to 90 as well (oh please, I think you have enough total level to call yourself a legit skiller, it is about time you started training these skills). You could then use the money from slayer to buy seeds to help raise your farming to 90.
If not, go for another 99 skill. How about cooking? It is super easy, and plus, you really do not have to do much. Seriously, you have 99 woodcutting, as if that was not an away-from-keyboard skill anyway.

If not 99 cooking, you could at least get it to 90; same goes for fletching. Then again, these are miserable stats to train, so I could understand if you do not want to train them.
I hope it all works out.
~Weekend Dude~