I managed the bluffer's park road on my fixed gear before (only ever tried once), but it was really hit and miss (nearly stalled/fell a few times) and I was *dying* by the time I got to the top. I would have stopped and walked but I was wearing look cleats and didn't want to walk up either. Its really ballsy going down that hill no brakes as there are some turns that are not really doable at coasting speeds if you're on a fixed gear.
I have done it a few times on my cross bike and its still a beast. I think my gearing is too high for it because I still have to grind up it with 38x23 as my highest gear. I am going to switch to an XTR cassette with 11-34 range soon so hopefully that will help. I may shrink my chainrings too or switch to a triple, but the crank and chainrings I am using now are good quality so I'm going to try to stick with them if I can. Ideally I'd like to be able to go up the bluffer's park road loaded with 40 pounds of gear without absolutely killing myself.