Re: Entourage data on external drive?
As long as your wife has her own eMail account, she may well be better off using her own Entourage identity on the home system. That will keep all her data separate from yours. The two Entourage databases (which include mail, address book, calendar, tasks, notes, rules, signatures, etc.) would be hard to keep in sync if you're both reading mail from the same account or trying to keep identical address books/calendars. (Since she'll start with a copy of the current database, it will start identical, but soon get out of sync as they both get modified separately.) You should delete your eMail account from her identity database configuration so she doesn't accidentally (or automatically from a Schedule) pull your mail into her identity, and you should likewise remove her eMail account from the Portable Mail identity. (This is done by selecting Accounts from the Tools menu.)
(BTW, I still suggest renaming her "Main Identity" folder to her name or something else she likes. Why? Since you'll be keeping your data on the removable drive, it's not inconceivable Entourage may be started without the proper database attached. Sometimes when Entourage gets confused about finding its database, it reflexively (trying to be helpful) recreates a new, empty one called "Main Identity". Renaming her active database makes sure that reflex doesn't tragically re-initialize your wife's data.)
(Synchronization hint: If you do what to share a few contacts or move a couple of eMail items between the identities, you can drag a message or contact from its respective list pane in Entourage and drop it into Finder (say, onto the desktop, or into a Finder folder.) That creates a .eml (mail) or .vcf (contact) file for each item. Once you switch to the other identity you can drag the file back into Entourage and it will get added to the current identity's database.)
By the way, while Entourage keeps almost everything (even most of its preferences) in the identity database, there are a few things kept in your account library: mail account passwords are stored in your Keychain, so when you use the Portable Mail database on the second mac you'll probably have to re-enter the passwords on that mac. It also keeps cookie settings and cookie-related preferences in the library (com.apple.internetconfig.plist), which it shares with Internet Explorer; you're not likely to notice that unless you use different "accept cookie" rules on the two systems or use Hotmail acocunts.
If your system at work is on a company LAN, they may have firewall filters in place to prevent you (or any other employee) from contacting the SMTP server of your ISP to send mail. You'd need to switch the SMTP server in your mail account (Tools>Accounts) to the company's SMTP server. You'd need to ask the company IT people what that address is. (It's also not impossible they'd have a block on the POP server ports, too; depands on the company's IT policies, etc.