I personally found Enscape to be the most convenient of all the renderers available as it seamlessly ties into Sketchup as a plugin, which of course in return comes with its own pros and cons. Trees and vegetation can be placed with the asset library piece by piece, for woods or natural distribution I am using Skatter, it also works with the Enscape proxies.
When it comes to materials I found myself making my own little library of “Enscape ready” SketchUp materials over time.This way I can preconfigure aspects such as bump maps and other values and have them ready to rock before even firing up Enscape.
If it helps you, I posted two threads here a while ago showcasing my workflow which also features Enscape: