My mother first started using a Mac about six years ago, and an iPad 3 years ago. I wrote posts on how I configured both (I need to update some links to documents lost when Apple set fire to iWeb) :
- OS X and Mac Mini tutorial and configuration guide 2007
- Elder Pad update: My mother's iPad continued 2011 and 2010
Her limited vision and ambulation mean she doesn't get that much use out of her devices these days, but she is quite proud of them. She particularly enjoys having her iPad on a prominent chair side stand. 
The one thing she most likes is to read email. She can't reply any more, but she likes to see it. The use of an ancient desktop  CRT running in 800x600 combined with the largest available font sizes means she can slowly digest whatever I send her.
The catch is there are too many sidebar items in Mail on iOS and on OS X 10.6 (Snow Leopard). It's too easy for her click on the wrong "box" and get lost in Drafts or Sent mail. There's an easy for fix for that, but I missed it for some time.
Since she gets her email via IMAP from her Google account  all I had to do was use the Labels Setting in Gmail configure to disable IMAP access for everything except the Inbox. That greatly simplified her iOS and OS X (Snow Leopard) Mail sidebars. (See below for a caveat on OS X Mail restarts.)
I was still left with a "Reminders" item in Snow Leopard Mail.app. I searched around for tips on how to remove that -- and found lots of frustration and some red herrings but no answers. Alas, this was an Apple usability Fail. Go to iCal (!) and in the sidebar look for "EMAIL INBOX", uncheck "Mail To Do". Restart Mail and it's gone. [Uh Oh: See Update!)
One Snow Leopard caveat to note: Between the Mail.app IMAP changes and the MobileMe removal I found I needed to restart Mail 1-2 times and OS X once to get all the changes established.
In iBook the Athelas font scales to much larger font sizes than some of the others.
As long as I'm on this topic, I'll pass on a few semi-related tips from some long delayed Snow Leopard/MobileMe maintenance 
- Sign out of MobileMe then restart. I think that's needed to clean out residual MobileMe settings .
- Set iOS Contacts back to old-fashioned (cable or wifi) iTunes sync - need to keep her SL desktop and iPad in sync.
- Enable the old Google Contacts to OS X Address Book sync. This is triggered whenever the iPad syncs by cable or Wifi and, with her tiny Address Book, it seems to work and manage conflicts pretty well. I'd be wary of trying this with a real world Address/Contact collection.
 (She doesn't interact with Gmail directly, though I do that remotely as needed.)
 Apple's decision to exile Snow Leopard users when they discontinued MobileMe was a nice gift to Google.
 I make the trip to the old country q3months, and computer maintenance isn't at the top of the list. This trip I got more done than usual.
 If I were setting her up today she wouldn't have a desktop of course. I must note though that in some way she prefers the desktop. The iPad is heavy and awkward for her; she needs something half the weight but the iPad 7 display is too wee.
 A lot of the things I've done to simplify her Mac/iOS use also work well for very young children and special needs users
Update 5/13/13: Ok, that Damned Reminders To Do thing is some kind of bug. It returned mysteriously. I wonder if it's somehow related to the end of MobileMe. There are about seven "ghost" tasks that show up without any attributes, and somehow display in Maill regardless of the iCal Mail setting. Resetting old SL iSync and disabling it didn't help. After a bunch of manipulations I got some message about 'server versions' not matching local versions. I might have gotten somewhere by deleting everything in Library/Calendars -- which is only feasible because she doesn't use Calendars. Alas, I had to leave before confirming this bug is truly squashed.