So, here's my time trial list!

Mushroom Cup
Toad Circuit: 1:23.672
Daisy Hills: 1:45.227
Cheep Cheep Lagoon: 1:43.235
Shy Guy Bazaar: 2:14.616

Flower Cup
Wuhu Loop: 1:32.601
Mario Circuit: 2:08.681
Music Park: 1:58.563
Rock Rock Mountain: 2:13.653

Star Cup
Piranha Plant Slide: 2:06.356
Wario Shipyard: 2:05.398
Neo Bowser City: 1:58.388
Maka Wuhu: 1:09.157

Special Cup
DK Jungle: 2:04.792
Rosalina's Ice World: 2:09.382
Bowser's Castle: 2:11.370
Rainbow Road: 1:44.519

Shell Cup
N64 Luigi Raceway: 1:47.591
GBA Bowser Castle 1: 1:20.211
Wii Mushroom Gorge: 1:44.467 (no gap fly)
DS Luigi's Mansion: 1:54.257

Banana Cup
N64 Koopa Beach: 1:36.775
SNES Mario Curcuit 2: 1:15.021
Wii Coconut Mall: 2:06.973
DS Waluigi Pinball: 2:20.679

Leaf Cup
N64 Kalimari Desert: 1:40.780
DS DK Pass: 2:17.644
GCN Daisy Cruiser: 1:37.320
Wii Maple Treeway: 2:28.226

Lightning Cup
Wii Koopa Cape: 2:23.616
GCN Dino Dino Jungle: 2:07.041
DS Airship Fortress: 1:57.700
SNES Rainbow Road: 1:15.805