Hi, and welcome to TripAdvisor forums
I recommend that you go "up" one level to the California state forum. Look at the Top Questions on the right. Read about the drive between Las Vegas and San Francisco. Then perhaps repost on the CA forum with your draft itinerary, including dates of travel and interests.
Taking a baby to Las Vegas will be a challenge as you cannot have your baby with you in the casinos. Perhaps ask on the Las Vegas, Nevada forum about things you can do while holding a baby.
What time of year? What are your interests? How much time do you have for the drive?
People take their babies to Las Vegas all the time They can go to the casinos and do so all the time. The Las Vegas forum will give you good information. There are children care facilities as well. Current vaccinations and a copy of the birth certificate is generally required to use them (however I find that generally kids who go there are a bit older.)
in regards to routes
the two routes I have taken are
1) Drive to I-5 and then drive to Bakersfield. I often stay overnight in Lancaster at the Best Western (very nice new hotel with large rooms; good breakfast; and very nice staff). Then i drive to Barstow and then take I-15 to Las Vegas. I usually do it with at least one overnight. Use Mapquest, to fill in the exact routes, etc. I stay away from Barstow now as too many street people.
2) Or if you want a scenic route, drive to Jackson, CA and take 88 across the Sierras to Minden/Gardnerville.
Then drive highway 395 to Lone Pine. From there drive to Death Valley National Park and then to Pahrump, which is about an hour away from Las Vegas. You need to be sure its not snowing the day(s) you are driving. A good interim place to stay is either Minden/Gardnerville or Mammoth Lakes.
But yes, babies are in Las Vegas - and the Las Vegas Forum can help you.
No - they cannot gamble (or be in the gambling area) or drink alcoholic beverages - which I assume you already know.
The tobacco smoke is rather hard on them, though.
On Jan 7th early morning we r planning to leave and 9th late night coming back. Any interesting place to cover..? If it is we will plan one more day extra