excellent choice with CO, we got tons of wapiti. make sure your boys are in good physical shape (able to 5-10 miles with about 100 lbs and not get too winded. i would also get in the mindset of walking in at LEAST 4 miles. many out of staters head in 2 miles or less thinking they are in deep enough. don't get me wrong some are very successful, buddy of mine shot a nice 5x5 1/4 mile from the truck on the way to our secret spot(8.5 miles in) also remind your boys that there is a 15% success rate for elk in colorado, resident and non resident