I've been doing the 2 hour adventure back to back and have 7 gnomes, the two gnomes as reward, and 5 more as drops from the adventure. I received 3 decorated trees and all of the other drops too. If you grow the undecorated trees, they will still drop the needed resources. I think you might want to keep the items from the pecan tree and the nutcracker as close to 99 as you can while crafting turtles cookies and wreaths. That's what I've been doing and it seems to be a pretty good strategy so far. I'm not sure how the energy expenditure will be for you. I hope you are able to finish.