Migrate one account from multi-user laptop to new hard drive

Question

Hello - I aologize if this has been asked/answered elsewhere, but I couldn't find it.
I have a MacBook unibody whose hard drive is reaching capacity; plus I am giving it to my daughter to take to college.
I am "upgrading" the machine with an internal SSD, a larger HDD, and making the optical drive external.
I want to move *just her account* to the new SSD. The new SSD isn't much bigger than the curren internal drive, so I want to put her Music, Movies, and Pictures on a 300 GB HDD partition and use the remaining 200 GB paritition for Time Machine backups.
I know this is a lot of things. I don't think I have any questions about how to do this physically -- I bought all the accessories from OWC, including an external enclosure for the optical drive and their USB to eSATA (etc.) connector to dupe the existing drive to the new drive.
The problem is that it's not a simply "duplication" issue. I don't want a clone of the old drive. To further complicate things, my daughter's current account is not an administrator account, and it needs to be an administrator account on the new drive (it's the only account that will be on the new drive.
"OLD" LAPTOP                         "NEW" LAPTOP
My account (administrator)          N/A
Wife's account                            N/A
Sister's account                          N/A
Target Daughter Account             Yes, as administrator
Her files                                     Yes, all of them
                                                       Photos, Movies, Music --> new internal HDD, 300 GB partition
                                                       Documents --> OK to be on SSD
Time Machine                                   200 GB partiion, new internal HDD
Applications                               Virtually all of them
Anyone else's files                      None
So -- am I making this waay to complicated? Should I just install Lion on the new internal drive, set her as with a new administrator account, and then drag the files I want into the locations I want? Do all the files associated with the Home folder have to live on the same drive?
Any help, much appreciated.

Answer 1

It's a lot to consider, but the short answer is that Migration Assistant or Setup Assistant will do what you want. Setup Assistant may be easier in your case. In any event what you propose sounds like a good idea.
My first question is how do you intend to connect the various drives. If you install the SSD and leave the MacBook's internal HD in place, that would seem to be the simplest thing to do. Install Lion on the SSD, then, boot from it. A new installation of Lion will call Setup Assistant to initially configure her user account and migrate data from her existing account - you will choose the option to migrate from another hard disk. You can choose the user account from the existing installation, and Setup Assistant will permit you to choose what to migrate. If you have the space, migrate everything, since you are about to remove the existing hard disk drive (if you do not have sufficient space, you will need to remove the existing HD and use it externally, since you will need to install the larger, empty one first).
Make sure you check the box to allow that user to administer the computer. It might be a good idea to promote her account to Administrator before starting any of this anyway.
Next, remove the existing HD and install the larger, empty one. Boot the MacBook, log in under her account, partition and format the HD using Disk Utility.
Drag her entire Pictures, Music, and Movies folders to the data partition. When you launch iTunes (for instance) hold the Option key. That will cause a prompt to appear asking you to locate her iTunes Library. Select the one on the designated partition. Repeat for iPhoto.
Make sure that all her photos and music appears as expected. Once you are satisfied it's working properly you can delete those folders from the SSD.
Next is Time Machine but after all this work that ought to be easy enough to figure out.
I hope this makes sense.
There are other alternatives including using Carbon Copy Cloner or the equivalent to clone the existing HD to the SSD, then deleting the accounts you do not need. It's up to you to determine if that is simpler.