I've climbed Longs Peak 7 times. It has been a lot of years since the last time I climbed / hiked up Longs. I am not a technical climber and do not use ropes or any other climbing equipment. The most common and easiest route is the Keyhole route. To avoid ice and snow ( which would require more technical climbing ) you would need to typically go up anytime from late June to early September. This route sees a lot of hikers, so weekends can be crowded. I like to leave the trailhead, off of Highway 7 between Estes and Lyons, at around 3 am, that way you reach the boulder field below the Keyhole just after sunrise. There are some large boulders to navigate on your way to the Keyhole and past the Keyhole there are some narrow areas and some steep spree fields. A great website for photos and information on routes and conditions is
www.14ers.com. Be prepared for all kinds of weather conditions and extreme temperature changes. Take layers for clothing and plenty of water. Most important, watch the weather closely. You do not want to be on top when it clouds up, usually by noon, high risk of lighting strikes. It is a beautiful hike, even if you do not summit. Enjoy