I would agree that neighborly help is no problem. One of the easiest to do. I don't "help" neighbors that are not active, so those are always available to fulfill a quest. Actually, I keep a list of neighbors who 1) regularly visit me or 2) regularly post basic-goods trades that appear in my trader (without tax). Those are the ones I visit regularly (I may not be in their world yet, but they're in mine so I also take their trades).
As for upgrading buildings, someone recently clued me in that many buildings that don't have "levels" but that you acquired in an earlier chapter can be upgraded. If it is a Chapter IV building, upgrading it to Chapter V fulfills the quest (the chapter IS the level). I just did that by doing a Smallest Room two times. It's a 1x1, so it cost me one Royal Restoration twice. Cheap! Upgrading Unicorns and Guards and other 1x2s is cheap too.