I am an old man. I think I'd be considered an experienced cyclist. I have no problem with taking the lane... and almost always do.
But on the other hand... I also have no problem slowing to a gentile roll and using the sidewalk to get around tree trimmers and other service personal when mixed with local traffic congestion. I also don't mind dismounting and walking my bicycle across a busy intersection at rush hour. My only hard and fast rule is to make it home alive. My wife depends on me being there... when my pay check arrives.
Being safe means knowing what is dangerous and why. Riding on the sidewalk is dangerous... particularly at any speed. Cars never seem to look for traffic crossing the driveways and parking lot entries. So... a car will turn in to their home or drug store never expecting a child (or adult) to be there. Pedestrians and small children move along slow enough to avoid the cars and to be easier to spot. But a quick moving silent bicycle will just "appear" in front of a motorist.