I don't know for sure if you can access the SD card through the USB connection to the camera for this particular model, but on most systems that is possible. It is, however, often slower than using a dedicated reader since the camera is not purpose built to be an SD card reader. It can also be very convenient to have a card reader if you get to the point where you are using multiple cards or simply don't want to have to plug in the camera.
As far as transferring to an iPad, Apple keeps things pretty locked down and only special proprietary devices are able to read photos off an SD card and move them to the iPad. They are pretty limited in functionality and generally read only. The only alternative to this is to jailbreak the iPad if you want read or read/write functionality over simple USB. The iPad hardware is perfectly capable, but Apple doesn't want people to be able to use external storage since they charge a premium for larger sized devices.
Another option would be something like an Eye-Fi card that would allow you to copy files to your iPad wireless through a WiFi network and client application on the iPad. I believe this can also get around the read/write limitation.