Endurance for a novice biker?

I'm buying a cruiser bike next week (Yes a cruiser nothing more so don't go listing better bikes) And I want to try for endurance, I know I can bike 10miles but I just moved and there are no sidewalks. I was wondering is the a time in the day (daylight) where the traffic won't be heavy? I live in a rural area. Also should I bike for time or endurance? And how long or far should I try to go. Keep in mind I'm a beginner.