Mini marshman was my first triathlon. The swim was a bit cold as it's an early season event, but a nice private lake. The bike course was flat and so was the run. Mostly narrrow country roads, so a fair ammount of twists and turns, but few if any hills. I am led to believe that the 1/2 IM is similar on the run and bike (just a bit further out!). It's also well know for being windy, which can make a difference on the bike. Oh yes and they had Jaffa Cakes at the finish!
I guess it depends how delicate you are - I'm lucky, so I can get away with a normal meal 5 minutes before leaving the house. The more prone you are to upset stomach/ cramps etc then the sooner and lighter you should eat - experiment and see what works.