Thanks for all the great advice on the hamstring. Yesterday instead of running I did weights and the elliptical. Good idea except I probably should have laid off the leg curls (ugh!). I did lower the weight and take it easy. After two sets I skipped the last set and any other leg exercises and stuck with upper body.
Last night and today I could still feel stiffness and some soreness (not really bad, just there) so I took today off and will also take tomorrow off.
Sunday will be a 5-10 mile long run, depending on how the leg feels. Per all the wonderful advice, I will go really easy and quit partway through if it doesn't feel right.
Since I have three 20+ mile runs in my plan, I will skip this one and work my mileage up for the next one. I am fortunate that I have plenty of time to adjust.
Thanks again for all the super advice!!!