What is legal and what is safe are two different things. However, un-controlled airfields represent about 95 percent of all the airports out there. When I enter an un-controlled field, I approach the pattern from 180 degrees opposite the 45 entry heading to downwind and 2 miles out, at least. I have already called CTAF to ask for traffic and runway advisories. Don't expect pilots or even UNICOM to be there, to be accurate or to even care about you. Look out for yourself by keeping your eyes out for other traffic. If you get no reply, yes, your method of overflying the airport is a good idea, but around a busy un-controlled field, expect traffic.
Point your nose to the end of your runway and not the mid-point. Turning dowwind directly violate the FARS because you are turning right, when all turns should be made to the left in the vicinity of the airport. Oh, well. Turn base, final and land. Call outs on every leg, leaving the runway and again when entering the runway or backtaxiing the runway.
Again, expect anything. People at un-controlled fields may enter the wrong runway (which may intersect yours), land on the wrong runway, land above you, not see you, land opposite you, take off opposite you, fly opposite patterns to you, enter above the field opposite to you when you are doing the same from the other direction, land their warbird on the field with no calls at all, etc. Un-controlled can be a crapshoot. My favorite un-controlled airfield is Avalon, Catalina Island in California. I've never seen it crowded and it's beautiful. The worst airport I've seen is Deland in FLorida, where parachutists scare me more than other pilots. Rod Machado has some good tips for pattern work in American un-controlled airspace. Tha AIM has a lot to say, but again, what is legal and what is commonly used for a particular airport are two different things. You may call an airport to find out more than the A/FD can tell you, especially about noise abatement procedures commonly used.
The way of the future...The way of the future...The way of the future...