I started a new playthrough recently, and I decided to make my base at the Elder altar. If your seed has an Elder altar on or near the water, I can't emphasize enough how awesome this location is for a base.
First off, it allows you to start a 20 x 20 (not including the ramps) stone foundation base much earlier in the game. i.e. before you start grinding for iron.
The sacrificial altar is an eternal hearth. It never requires fuel. I fit a cauldron and six cooking stations over the flame.
The four columns are great for anchor points for building out the base. They give you 8 meter height of "grounded" structure.
I've seen some people build some really nice basements under the stone. Right now, I just have my bench and forge upgrades down there.
If you're new to the game, I can't think of a better location for a base.
Source: https://www.reddit.com/r/valheim/comments/oe73pn/making_base_at_the_elder_altar_is/
