Always fly in to a high and hot place with an instructor first. Things to remember are to read the book, lean on taxi, certainly lean for maximum power during run up and subsequent take off, lean during the climb too. Roll/descending air may be encountered off of adjacent mountains and actually experience descent during climb out. Don't ever assume that clearance will be certain over mountains or fly into blind valleys/canyons because of the danger from roll/descending air. You may need to circle to get out of low level terain over higher. You may need to search for the direction of climb to get best climb ie; you may find that the aircraft will climb best facing the direction of wind rather than the direction you plan on departing. Always, always, check weight and balance calcs. Check before you fly in that you can fly out having regard for weight/balance and length of runway/density altitude. Landing/take off may well be turbulent close to mountains.