Can anyone quote/point me to some sources in Chazal that say we should enjoy God's nature and creations? Something to suggest that they are not distractions from serving God, but a proof that they are a means to serving God. I know there is a Chazal that if you stop learning to gaze at a tree it's a bad thing, but is there something to the opposite effect?
Yerushalmi Kiddushin 4:12
רבי חזקיה ר' כהן בשם רב עתיד אדם ליתן דין וחשבון על כל שראת עינו ולא אכל.
In the future, a person will have to give an accounting for everything that his eyes saw and he didn't eat.
The Mishna which you referred to from Pirkei Avos has alternative interpretations which do not have the implication of asceticism. One example is an approach which says that his problem was not looking at the tree - his problem was that he stopped learning when he looked at the tree - even when he looks up from his books, and looks at the world which G-d created, he should be learning from the world. The world is also a reflection of an aspect of Hashem's will, and looking up at the tree should still be an act of learning.