The Saris Bones racks were supposed to be good, but I don't know if they actually were or if I got tricked by marketing. IIRC, they're quite pricey for trunk racks. I would go with the in-trunk method if it fits.
Gloves, patch kit/tubes, pump, definitely. I'd also get a basic multi-tool. 1/2 finger gloves with lycra backs and a leatherette palm are pretty comfortable and cool. I would hold off on the shorts until you figure out if you need them. They're a big improvement, but you might not ride long enough to care.