Thanks for the tips. I do try to stay away from the easiest gears unless I REALLY need to use them...this means I try not to use the smallest chainring unless absolutely necessary (didn't touch it on yesterday's 50-miler). I also usually do keep pedaling on downhills to try and carry some speed into the uphill that follows (can be a problem in some groups...I notice a lot of people don't do this, I pass them, then they pass me going uphill--ugh). As far as shifting down earlier, that may be one of my issues...I do find that sometimes I wait a little too long and then have to shift down a few gears in quick succession, slowing way down in the process (though if I downshift earlier it sometimes feels like I am spinning and going nowhere). Not sure if my primary difficulty is more legs or cardio, I think it is probably a bit of both and will have to try and pay more attention next ride to figure out which one seems to be the real limiting factor. The standing to climb may be something I need to work on...I generally prefer to climb seated and feel sort of awkward if I try to stand up to climb.