About to move the exchange 2003, wanted to make sure my plan is correct.

Hi all, I am about to switch from exchange from Groupwise and would like to make sure all my ducks are in a row.  I figure this would be a great place to make sure I have all the steps down as I should.  Also I have some questions.

Setup:
I'm putting exchange server 2003 on a dedicated machine, should have the specs to run it.  One of my big questions is whether it's worth doing a front end, back end solution in our company (180 employees) or wheter I should just have them all on this one.  Lately, I've been leaning towards the latter, at least at first.  Any big problems with this?

Steps (summarized):
1.  Setup base windows 2003 server
2.  Extend the schema on my main DC with the master roles using the exchange install disk.
3.  Install the windows components needed and install exchange on the server.
4.  Edit the register for bigger data stores (I have standard edition)
5.  Configure the base server as needed.
6.  Use the quest migrator (I don't expect anyone to understand this part).

On step four I have a question.  I don't know how to configure a RPC over HTTP on a single server.  Any pointers or is it easy?  I know most documentation and stuff always shows this being done on a front end only server.  However, I've read this isn't a requirement.

Thanks in advance!