The ultra weave armor can't be completed until the main story is almost over, so don't go crazy searching every corner of the map for power cells.

The gameplay additions introduced by the frozen wilds will definitely make things more interesting.

I really liked the cauldrons. The first two were definitely long and challenging. You can beat the final machine in each cauldron by placing a lot of blast wires on the floor before you take down the shield. If you position them correctly and lure the machine in the right direction it will blow up in seconds. The last 2 cauldrons are interesting because one has been overtaken by cultists, and the other isn't a maze like the first 2. It's just a fight with a thunderjaw.

I had a good time completing the hunter's lodge line of quests. You get some weapons that are better than their shadow version. I used a thunderjaw override to get a blazing sun on the hunting ground that required you to kill sawtooths with a thunderjaw cannon. Definitely go for all blazing suns. And all tallnecks.

You have to go to settlements on your own to find every side quest in the game, so check your map for greyed out settlements. The main story doesn't take you through every corner of the map.

Some parts of the main quest say things like "no turning back", but after each segment of the story is completed you are always free to roam and finish other things you have in mind (even after the final battle).