first "real" road ride

[OakLeaf]

Are you sure your shoes aren't putting pressure on those tendons? Not rubbing, just pressing. Some of my running shoes do that. I just had to re-lace a pair of shoes because I bruised them pretty hard on my second-to-last run.

+1 on not worrying about whether a hydration pack is fashionable. I don't like to use one on the bike either (weight on my back is the #1 reason, and heat is a close second). But I sweat and I get dehydrated very easily, so on hot days and/or longer rides you bet I wear it. There was a 42-miler I did on a hot day last year when I went through both standard size water bottles AND my 60-oz Platypus and was on "E" by the time I got back.

Arm fatigue is probably more conditioning than it is form. You should be using your arms when you ride, particularly when you're climbing.

Descending, you're much MORE stable in the drops. Your CoG is lower, plus you have better access to the brakes if needed.

Sounds like you had fun! Yee-ha!