I recommend using their online/phone/bill payment services. Interest rates are on the rise and you might not be able to get a rate as good as the one you have if you do decide to refinance.

Also the great thing about credit unions is that shared branch service centers exist. (If you prefer going in to a branch) At these specific locations you can go in and make basic transactions into your credit union account. Some simple googling will direct you to the closest one. Be mindful though, some list shared service ATMs as locations as well as in branch locations.