Debra - I think you will be on the same flight into Durban as me again. I did route tours in both directions. It's possible to do the tour and have plenty of time to register and visit the Expo, leaving Saturday for parkrun and rest.
Zuvai - definitely do the tour. It's better to know what the hills are like and there are some iconic points on the course that it is nice to have time to visit. The tour guides tend to be Green Numbers who will have good advice. If you are lucky you might even get our own Slow Duck as a guide.
North Beach parkrun is amazing, Mr Z. So many people! It's quite hard to get a clear run, as so many walk and it can be quite congested. The image that is on the North Beach parkrun webpage was taken during the year of my first Comrades and numbers have swelled quite a bit since. http://www.parkrun.co.za/northbeach/ I'm just visible in the green and white vest near the middle and there are a few other Comrades runners in the picture, too. Have fun at Brockenhurst.