When the server launches the Sheriff's Department will only have one station. The station is based in Davis and portrays the LASD's Compton Station. When the server expands enough a new station will open, preferably in Paleto Bay. With Paleto and Davis, Sandy Shores would be right in the middle.
I'd suggest to have Sandy Shores as a station to spawn at and be able to process arrests at. @jack
So ultimately I'd say that the Sheriff's Department could have three stations down the line.
Regarding the travel time, I like the idea. It would make some really nice travelling RP and I'd see myself creating a character that lives in a van and travels places.
I'd say that the roleplay should be on a case by case basis. If you are a deputy travelling from Paleto to the city, you can roleplay it as it is or not even bring it up. If you are a traveler, I would love to see it roleplayed as 3-4 hours to Paleto and 2-3 hours to Sandy. It would be also nice to see truckers roleplay it as a realistic as possible and make the route a couple of hours long (ICly).