I have a bit of a problem that, fortunately, I don't believe very many people have to tackle. Unfortunately, I have no idea how to approach the issue
I've been building up my endurance (read: saddle tolerance) for the past couple months now and I think I'm ready to start pushing for longer and faster rides. The only problem with this is that I'm not exactly in any shape to start measuring how much effort I put forth or how far I've traveled. They don't sell those clip-on monitors for heart-rate or distance traveled or anything here, and the roads don't have any distance-marker signs or anything. The locals are great for finding places to ride, but their sense of distance is... strange... It's not uncommon to get 20-50 percent variance on distances depending on who I ask.
So with no sure way of measuring anything besides time (since I always have my watch on), where do I go from here for improving my performance? Do I just keep riding "for the sake of riding"? Is there any way, besides interval training, to reliably and incrementally improve? What's the best way to interval train since I can't track speed or heart-rate?