You should be using Iron Armor & Weapons (since IDK) - and since you're getting the wolf raids, you seem to have done bonemass already. When in the mountains, try to keep the frost buff up and always use the best possible food (meat from a sea serpent can help a lot). As for safety/portals there: There should be some large, steep rocks around. Look out for those, build a small shack with stake walls & a roof up there as high as possible with some ladders/stairs down. Just always leave 1-2m of the stairs out so you will need to jump up there, which mobs cannot do. With that setup you should be fine for getting started there. Just always be cautious and possibly don't run around during snow storms /at night. You can build more of those rock-safe-spots all over the mountain so you can quickly get onto one when you get another wolf raid.