$ sudo cgpt add -i 3 -u $(uuidgen) /dev/sdband avoid taking the trip to Wonderland all together.
2. To identify the current rootfs & kernel partitions:
$ rootdev -swill return the partition mounted as / like this:
/dev/sda#where # is 3, 5, or 7. So, just subtract 1 from # to identify the current kernel partition.
3. Interestingly, the Acer C7 seems unable to boot from an SD card in the on-board card reader. I have successfully created bootable SD cards using the slot, but must move them to an external USB reader to boot from them. The only conclusion I can draw is that the firmware can only boot from a device connected via USB and that the card reader slot is, in fact, not USB.
4. To fix the erratic trackpad behavior in Ubuntu:
sudo gedit /usr/share/X11/xorg.conf.d/50-synaptics.conf
after MatchIsTouchPad "on" in the file, insert these lines:
Option "FingerLow" "4"
Option "FingerHigh" "10"
Reboot and the problem should be resolved. However, it's possible that a system upgrade (i.e. 12.04 to 12.10) may wipe out this change, so keep that in mind.
5. Another factor to consider regarding Linux Distros on Chromebooks is the version of kernel that the distro ships with. Since Google's current CrOS kernel is version 3.4.0, I've generally stuck to distros that included kernel 3.4.0 or earlier. While the CrOS kernel apparently incorporates some features of later kernels, for optimal compatibility, 3.4.0 seems like a good logical target.
Postscript - 05/30/13 - Just ran across this excellent explanation of the issue:
I was merely speculating based on reasoning and experience.