> I re-read the rules.  Turns out that after you finish a story, you can
> tap on the Story node again and it will give you missions (the
> current ones are all clear a fixed song at rank S / combo S / 5 times)
> with prizes attached to each.


Yes, 'Score Rank S' is 2000 friend points, 'Combo Rank S' is 30k gold, and 'Play five
times' is 1 loveca.


But you can play it on any difficulty.  Playing on EX will get you more event points,
but you could theoretically play on Easy five times to get the 1 loveca if that's
all you were after, and would only be out 25 LP.  For Happy Party Train, I played

once on EX to get the Score S, and then once on Easy to get Combo S because I can't
combo it yet.  Then went back to EX.  I'm assuming there will be plenty of time to
play each of the locations 5 times each on EX, unless there's a second page to the

map. 


> There is only one Challenge node, and it gives a random song (1 out
> of 9 event songs) each time you play.  It is where you try to go for a
> high score for the event high score ranking and you get a prize for
> clearing the node 5, 10 and 25 times.


1 Loveca, 5 R seals, 10 R seals, I think.

> If you try to clear each node 5 times (to get the prize stone) with 4x
> LP you can burn through a lot of LP.  Not sure if this means the score
> will grow quickly, or people will not play at 4x, or not go for the
> prize stones...


Not going for the stones would only make sense if you're very pressed for time, since
playing 5 times at any difficulty setting will get you the stone for that location.


--Robert