Hi there,
Glaciers and tundras are my favourite embark site -- probably 70% of my fortresses are founded on those biomes. Here are my suggestions:
1. After breaching the caverns multiple times and dying from surprise invasions of cave crocs/crundles/elk birds, I decided to try a different method of setting up farming. Instead of looking for existing mud, I decided to try making my own. I dug a large room next to a cavern pool, and then dug a narrow passage to the pool, smoothing and fortifying the tile bordering it. I installed a floodgate to regulate the water supply. Using this method I could flood a room and leave it covered with mud for farming and not breach the caverns.
2. I usually bring 36 or more of ale, rum, wine and beer on embark. Alcohol is more important than meat since you can always kill something on the map for it but brewing alcohol needs plants, which you can't farm above ground. Thankfully you are on a calm biome and not a savage one -- yetis are really tough foes at the start.
3. Traders were a really easy solution for me when I wasn't confident enough to dig to the caverns. Just make lots of stone crafts to buy all your required supplies!
4. You might need to, err, dispose of early migrants if your food and drink starts to run low before you've found a way to replenish them.
5. Drop the embark axe and bring more lumber for constructing beds. You might want to reserve one log to make a training axe for chopping down those giant cavern mushrooms.
6. Some sites are cold enough to kill your animals and dwarves if they stay out too long.
7. If your embark site has no traders, there is not much reason to build a substantial amount of your fortress in upper z-levels. For this reason I tend to build my fortresses near the magma sea nowadays. I'm closer to my food supply and the lovely lovely magma, and if you are thoughtful enough to not dig straight down and instead shift your stairs around every few z-levels, you will leave yourself extra breathing space when goblins come knocking on your door. (This might leave you more exposed to HFS, which I haven't had much experience with, so take this with a grain of salt.)