I will say it sounds like you are trying to cram in a whole lot of stuff in not very much time. Are you sure you can't add another overnight? Even on a rush schedule, I think you'll help yourself out a ton by staying around Paso Robles the first night, stay in DV the second night, and finish out your trip to Vegas the following morning.
That said, hotel reservations are a little tricky. Bakersfield isn't usually a place where its tough to find a room, and for this trip I wouldn't want to make reservations either, in case you discover you have bitten off a little more than you can chew that first night. No reservation would give you the flexibility to change your schedule en route.We were assuming we can play it by ear as far as accomodation is concerned, hoping to find something. is this stupid?
However, since this trip is over the holidays, it is more likely that rooms would be filled. I'd say how close your trip is to actually falling on Christmas will be a significant factor in finding a room. If its midweek the week before christmas, I wouldn't worry, if its the weekend right before christmas, I'd lean towards making a reservation.
You can still get on the base. I've been on it a few of times in recent years, a couple times for work and once for leasure. You'll have to have your ID checked and your car searched, but you can otherwise go on the base. Until I was there, I never realized just how much of a small city the base is - complete with its own high school football team.I am not sure if you can even visit the AFB in these days of higher restrictions. Perhaps someone else can jump here on this point, but I really don't see how you have enough time.
I believe there is a museum on the base, however, I don't see how you'll have any time to visit. You're looking at at about 7 hours of driving from Bakersfield to Vegas via DV. Its going to be hard enough to make it to Vegas in the early evening with just quick stops in DV, I don't see how you'd be able to add anything else in to this leg.