You might want to put on a 39 or a 42 tooth chainring if you plan on riding a fixie. The hills aren't particularly steep, but they are fairly long. The steepest and longest stretch is coming up Terwilliger from Lake O, northbound.
It's a nice ride, though. The off-street trail that winds through Tyron Creek park is lovely. Just keep an eye peeled for joggers and walkers.