Hi! Completely new to home DIY.

Most of my house is carpeted over original hardwood floors. I want to rip up this carpet and restore the floors. We've pulled up a foot or so of carpet in a corner of one of the rooms and the wood floor seems to be in decent condition, scratched up a bit and definitely in need of sanding and refinishing, but nothing weird looking about it.

Should I remove the baseboards for this? Whats the best way to remove them and to reattach them? They're wood and not in the best cosmetic shape-- if I remove them, would it be a good idea to refinish them before reattaching?

What do I do if there's a gap between the floor and the bottom of door frames? Are there any wood floor red flags I should keep an eye out for that would indicate that this would be a bigger project than expected?