quick summary: ***1. move moms stuff from old macbook pro backups during snow leopard & new macbook air stuff with lion back to old macbook pro (& allow her to keep using lion). ***2. move dad's current state (of snow leopard) to new macbook pro (with lion on it currently). i believe that the move from 500GB+ to 128GB SSD should be more than enough space for all of his stuff. 1. so, i bought my mom a macbook air 13" (128GB SSD) about a year ago because she was complaining about some shoulder pain so i thought it would be easier for her. 2. then, i took the macbook pro she was using and put my dad on it (it has like maybe 500GB standard hard drive only...prolly from like 2010 or so...). 3. she has a huge itunes library & i basically shifted the bulk of her files to an old 1TB time capsule (rerouted her itunes/iphoto/etc library to there, etc). i hoped that it would automatically & wirelessly add her new additions to the time capsule (but of course it didnt do that consistently & she now has multiple libraries...i set it up the right way, but it just didnt work every time she imported stuff & its too much work for me to keep telling her to go select her old library before importing files). meanwhile, my dad has less than 1 gig in his itunes & iphoto combined (stupid me for even doing all this). 4. i set them both up for automatic hourly backups to the time capsule but am unsure how consistently that has been going on (i think my dads gets backed up hourly, but i think my moms shows that it hasnt been backed up in forever). 5. so now, she doesnt complain about her shoulder anymore since switching to some B12 vitamins and i want to swap their computers so she can use hers happily like she used to (she always liked doing projects, burning discs, & all sorts of things). my dad could care less as long as he can use youtube & hotmail & medical sites... 6. now i just bought 2 slim portable external hard drives that i want them to use for backup and want to know if i can use these drives to swap their computers & put them back in the same state theyre in now. 7. i was hoping to first do a full backup to the drives on both, then my dads stuff should be easy to put on the macbook air since its almost nothing. but for my mom's, i was hoping to start her with the last full backup i did on the time capsule before the initial change (so she can get her original itunes & iphoto, etc) THEN somehow add all the changes she has made since that time that are currently on her macbook air (thereby collaborating her whole mac experience into 1 "timeline"). 8. additional useful info: i THINK my dad is currently on snow leopard & i KNOW my mom is currently on lion. i THINK my mom's last backup (on the time capsule) was snow leopard. anyone have any suggestions? the new drives are usb 3.0 (750GB each), the time capsule can use ethernet to (somewhat) speed up transfer rates, i also have a thunderbolt cable & mac firewire cables. thanks in advance!