I start by sailing up to a "safe" biome that borders the one I will be exploring. I drop a workbench and a portal then connect the portal. Then I will head directly into the new biome and look for points of interest and mark them on the map. When I'm starting to get uncomfortable I make a 90 degree turn, travel the map reveal distance, turn 90 degrees again toward the boat and portal and return. I'll go a bit more down the coast and repeat the process.

After that I deconstruct the portal and the work bench, sail a bit further down the coast, and repeat. Most of the time I can get the recon on the entire land mass done in relative safety and then decide where to begin exploitation.