Do you knees a favour and run a dingle cog.Your knees will eventually pay the price from braking and skidding and pushing too high a gear up hills.

Do yourself and everyone else on the road a favour and use a pair of ****ing brakes. A pound of brakes won't make your ride easier, and you can just reserve their use for emergencies, there's nothing stopping you from punishing your knees any time it's safe to stop like that. Having a set of brakes on your bike isn't going to make a 100 mile fixie ride any less of a ride but you will be able to save your skin so you can ride the next day.

I don't think riding a 100 miles on a geared bike is easy (otherwise everyone would be doing it) and I don't think riding a 100 miles on a fixie makes you a better cyclist (or person in general) either, so you'd be wise (IMO) to drop that kind of attitude as well. Like something because you like it, not because you think it makes you better than someone else.