contacts & calender sync?

Just purchased a nexus 7 for my mum ( joint bday / mothersday gift ;) )

and its awesome, she loves it, however there's one thing it doesn't do that would make her life mega easy from what we can see, and that's a calender & contacts sync.

Shes a care worker, so what would be great is if for example she could create a contacts page for each client, then using a calendar mark which client needs to be seen at what times, which leads to the clients contact info,

so for example she could add a client :

Dorothy
Yellow brick road
land of Oz
000-000
tel number - 00000 000 000


Then say on a calender she could tap monday 9am, add Dorothy, and its all registered with links to address / google maps ect.

while the calender on the device is good, shes often seeing the same client multiple times during a week, so just being able to add via contacts would be great, is there any app or app combos that would allow this?

Thanks in advance!