The transitions and cutscenes in this game are super slow, you want to avoid them as much as possible. You need to collect the 42500 FP at once and then buy all three floors at once. To further avoid the train, you should pick one minigame and play it until you have the points. I did the sliding puzzle game at the craft store in the shopping district - it gives you 600 FP if you complete all six puzzles within the time limit. I was able to average 20-25 seconds per set (faster if I got lucky mixes) with only a little practice. If you aren't good at sliding puzzles, the sushi game or the sketchpad game also have pretty good FP/time ratios. The sushi game, if played well, gets you 500-750 FP in 45-60 seconds, and the sketch pad game has similar results. They both are slower to play than the sliding puzzle game, though, so that is my recommendation.