I like these:
"I am a wanderer and a mountain climber. I do not love the plains, and it seems I cannot sit still for long." - Friedrich Wilhelm Nietzsche (19th-century German philosopher and classical philologist), "Thus Spoke Zarathustra"
"Live each season as it passes; breathe the air, drink the drink, taste the fruit, and resign yourself to the influences of each." - Henry David Thoreau, "Journal"
"Do not burn yourselves out. Be as I am - a reluctant enthusiast... a part-time crusader, a half-hearted fanatic. Save the other half of yourselves and your lives for pleasure and adventure. It is not enough to fight for the land; it is even more important to enjoy it. While you can. While it's still here. So get out there and hunt and fish and mess around with your friends, ramble out yonder and explore the forests, encounter the grizz, climb the mountains, bag the peaks, run the rivers, breathe deep of that yet sweet and lucid air, sit quietly for awhile and contemplate the precious stillness, that lovely, mysterious and awesome space. Enjoy yourselves, keep your brain in your head and your head firmly attached to the body, the body active and alive, and I promise you this one sweet victory over our enemies, over those desk-bound people with their hearts in a safe deposit box and their eyes hypnotized by desk calculators. I promise you this: You will outlive the bastards." - Edward Abbey, "Desert Solitaire"