Options for new line path from breaker box
It's all a matter of what's easiest/most cost effective for your situation. An electrician (or two or three) with hands and eyes on-site will be able to determine that far better for your house than a bunch of people making guesses from the other side of the internet (especially since we don't even have pictures to guess at).
In my house, I've run wiring down from the first floor panel, through the crawl space and up into outlets, switches and the ceiling of the first floor for various upgrades.
I've also gone down to the crawl space then all the way up an interior wall to the attic to drop into the walls and ceiling of the second floor. Sure, a trained electrician with a lot more experience than I may have chosen a different route, but I did what worked for me, and what I saved in time, effort and frustration (trust me, there was plenty of those three spent) more than made up for the few extra bucks in cable that I had to use.
Your house may be totally different.