Pick one of the combat overhauls, whichever one looks interesting to you. Then pick fast travel. Any other mod is up to you, but I highly suggest the first two.
I love Witcher 3, but the amount of people that didnt finish the game was some huge figure (60-70% iirc.) compared to those that buy it. I left the game a handful of times myself before I just sat down and played it all the way through with mods. The one mod that listed out all the rewards that POI's have probably saved me the most amount of time (behind fast travel) so I wasnt spending thirty minutes traveling to, killing whatever, and traveling back, all for some basic ass crafting materials. Theres just a lot of shit thats distracting in Witcher 3, and anything you can do to limit those distractions by choice is a good thing imo.