Gary,
There are significant challenges to managing a 2,000-name mailing list through Outlook.
One of the big ones is managing unsubscribes and bounces. Email marketing software automates these processes, but you will have to do them manually. Under CAN-SPAM, you will have to process unsubscribe requests within 10 business days. You will probably need a method for keeping someone in your database (they might be a donor, want to get hardcopy mailings, or want to be on other email lists) while suppressing them from this particular mailing.
Processing bounces manually can be very time-consuming. It usually requires opening an attachment on each bounced message, finding the email address you mailed to, discerning whether the problem is temporary (e.g., full inbox), permanent (bad email address), or resulted from a typo. If either of the latter are the case, you then need to manually update your address book.
You need to be sure you're sending 2,000 separate messages, rather than putting multiple addresses on the BCC line (or, God forbid, the To line). Using the BCC line is a big spam flag. You're also limited in how many addresses you can BCC at once.
And, as mentioned earlier, you need to see what your ISP's sending limits are. Some monitor the number of messages sent per hour and will ban your account if they decide you are a spammer.
None of this guarantees that your message will reach the intended recipients. It just deals with the mechanics of sending your messages.
I've posted links to articles on email delivery
here and on spam
here. See if these help.
Robert