Graeme,
A few of us have gone to the NW200 each year for quite a while. Taking the bike over is good fun, especially if you ride up the Antrim coast. You're at the mercy of the weather, of course, and being Ireland it can really rain. However, we've had some lovely sunny spells for the long weekends which we used to take there. Getting accommodation in Portrush/Portstewart can be difficult, and many people book up their favourite places well in advance. It is easier to get accommodation a bit away from the circuit towns - small places on the Antrim coast such as Cushendun are very nice.
As an alternative to biking over you can fly over by Easyjet from Glasgow on the Saturday, hire a car to take you up to Coleraine, park it there for the day and walk to the circuit. Stay in a Travelodge or similar and fly back the next morning. Cheap and cheerful.
Having said all that, it seems so many people all have their tried and trusted favourite itineraries for going to the NW. However you go I'm sure you'll enjoy it.