Salam.
Phander is an amazing place but best time to visit is during springs or summer. Still, the advantage of going right now is that its off season and so you will find less tourists.
You will take the Hazara motorway and then KKH till Gilgit. I have never travelled to Gilgit via KKH and always took the Babusartop route since it's more scenic, road conditions are comparatively better and travel time is less. BUT... I have heard that KKH is a lot better now and only 5-10% road is not paved rest has been layed out. Also expect to wait for a few hours around the Dasu dam area since they stop the traffic during rock blasting. But otherwise the few YouTubers I follow who have done winter tours this season everyone says that KKH is fine to travel on now.
Trying to make it to Phander in one go is hectic and you should not do it if you aren't on a strict timeline. Possible stay options include
1) Besham
2) Chillas
3) Raikot Sirai
4) Jaglot
5) Gilgit city
I suggest you take it easy and setoff at 8 am and stay in either Jaglot or Gilgit. Distance to Jaglot is around 450 kms from Islamabad but since stop overs are expected near the dam site hence take it as a given that you will reach there in more or less 10-12 hours.
Besham on the other hand can be done in under 5 hours and the road is absolutely fine till Besham.
Gilgit is a little ahead of Jaglot at around 515 kms from Islamabad and travel time should be around 12-15 hours (including breaks and stop overs....can be more)
Phander is around 160 kms from Gilgit and usually takes 4 and a half hours from Gilgit.
So if I were you I would take it easy... enjoy the scenic views of KKH and stop at either Chillas, Jaglot or Gilgit for the night.
Expect subzero temperatures and prepare accordingly. Petrol is easily available but it's a good idea to get your tanks full as you empty up to half.
Yaris will go there easily without any issues.
