Safest is under indestructible area, like cutting out under the elder's shrine but you can also dig under instances (cave, crypt, etc).
Next safest is inside a ring of terrain wall. Flying stuff can still get in.
Next would be a moat (some mob can get over a moat, eg 2 lox one can fall in and the other walk over the first, this isnt smart AI but it happens by incident).

workbench and fire spam prevent spawns but not raids.
All that leads to ..

if you get a raid, you need a nearby but out of risk to your home combat area you can play in. Go there, fight the raid off, away from your home.

Gjall specifically will ruin everything. They are going to get at least 3-4 shots off and it will aoe damage a lot of stuff in the aoe. Gjall are easy to kill with the crossbow and shoot the red area -- from stealth if you can.

The meadows specifically is rigged to not allow some raids or something. I didn't follow all that in the patch notes. Being in the meadows is the safest base, if I understood that bit.

-> wards supposedly reduce damage done to their area affected items. I don't let my base take damage and have not tested it.

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should you build in marble? If you want to. Wood is high risk if your base is not completely monster proofed. Stone and marble either one can take enough hits that you can avoid major problems but will have to repair it. A new crafting thing damages all but black marble, but you can dump it out in the woods or something.

I advise making the base more monster proof with raised terrain, and possibly, not bothering to do a full base in the mistlands. Just do a crude outpost and if it gets trashed, a quick fix to put it back together.
Try to be near some pulsing roots.