The following quests need to be completed.
-(Finish current quest from Papa Smurf)
-Gather 10 Wood (either from Timber Smurf, as gifts from friends, as rewards from Lucky Smurf, from a Wood Raft Voyage or by buying them for Smurfberries)
-Harvest 10 Magical Raspberries
-Place the Hot Air Balloon
-Travel to the Mountains
Once you are in the mountains a new adventure starts with Grandpa smurf. Please check out the mountains article.