The sky at class 4 is still much, much better than 7, and you'll be able to see the Milky Way.
But if you're able to then sure, go for the darkest sky you can get!
I grew up just outside of Washington DC, which is Bortle class 8. The first time I went out in the country and saw it as class 4, my reaction was "WOW, that's what the Little Dipper looks like?!" All my life I had only seen Polaris -- never the fainter stars that make up the whole constellation. You'll really appreciate how people in ancient times connected the stars to imagine fanciful creatures in the sky.
I've also had the fortune to see the night sky in the southern hemisphere under truly dark, Bortle Class 1 conditions, and it was the most amazing thing. It really is as much better than a 4 than a 4 is from a 7. The Milky Way, especially if the central region is in view, becomes a commanding presence in the sky, and you just get lost in it. There are so many stars it's hard to contemplate how the sky contains them all and yet is still so dark.
There's tons of resources out there for following the sun and moon movements. One of my preferred tools is the Photographer's Ephemeris
, which lets you pick a location on the map and then computes not just the times of sunrise/sunset and the Moon phases, but also where they will rise and set and how high they are in the sky at different times. I really like it because it's fast and easy to use.
You'll also want to try to mind the weather. Not just for clouds, but for the clarity of the atmosphere. Dust, haze, or water vapor will reduce the clarity of the sky and dim the stars. In the desert though it will probably be quite clear if there isn't any dust.
Also I should say, so that you don't have false expectations, that the Milky Way will not look the way it does in photographs. The camera picks up a lot more light over a long period of time, and thus shows fainter details, and colors, which are not so apparent to the eye. However
, it is still an absolutely spectacular sight, and in very many ways is better in person! You will not be disappointed!