I have varicose veins due to multiple pregnancies. (You haven't lived until you've had to wear support hose and a maternity girdle in 95*F heat and 100% humidity.) Interestingly, after the pregnancies, the more I exercised, the less the veins bothered me. They look horrible, but I haven't had any problems with them for the last 25 or so years. I wouldn't have the surgery for cosmetic reasons, but I certainly would long since have gotten it if they were painful.
Since your veins obviously do pain you when hiking, I'd definitely discuss the situation with your physician. Be sure to tell him/her about your activities and that you don't want to give them up. Maybe you can schedule the surgery in the "off" season so you have plenty of time to heal up and re-strengthen before spring/summer hiking.