Notes
Short version: OMG OW OW OW.
Longer version: went and ran the two loops that will make up the course for the 50K I'm doing next month. On race day, we'll do them each twice. The south loop, the longer of the two, started out deceptively easy and beautiful, on slightly rolling paved trail through woods, but then it spat us out onto the beach around mile 4.75, and we ran on sand for about a mile, then did another segment of more technical trail that was pretty but required a little more concentration. I was still feeling good by the time we ended that loop, around 9.5 miles, but it apparently did take a toll on me, because partway through the second loop, just a paved out-and-back 6.5 miles, I was DONE. Did the whole thing pretty slowly, since there were only a handful of us and we were all following the RD.
My core is shot. In the car afterwards, my shoulders hurt just driving. I'll make it through the race, but it won't be pretty.