Hi,
I am a rider also, I do hunter-jumpers and dressage. I have not found that riding effects my skating at all, although some of the falls I've taken have caused me to miss a skating lesson here and there! ;-) One thing I have found is that my knees tend to tire more on days I ride and then skate, but I have knee probems from years of ballet. I think the posting trot / jumping courses is what bothers my knees and tires them, and then all the knee bending in skating accentuates that...but that could be just me! ;-)
Congratulations on the new horse, I just had.to put my girl down :-( Hope you have tons of fun!! What kind of riding do you do?