Thanks for the replies everyone, sorry for the late response, there have been too many electrical storms here lately to use the computer.

@Shonky:

I do not need the router functions, I was only going to use the WRT54's since they are cheaper than the WAP54 access points! I hadn't thought of the point about saving on a switch though!

The building separation is ~50m line of sight, two brick walls and a steel frame / Hardiplank wall to get through, would a MIMO or pre-n setup be required in that case?

@tman:

If I use WDS to connect the two routers as you suggest, then the way I understand it, I could bring a WiFi laptop onto the network later, is that correct?

Thanks.

(Sorry for the lack of quoting, I had a quoted reply ready but it seemed not to want to preview or even submit.)