Do you need a full-height tripod, or would you be content to set your camera on a rock if you could get it level?
Your basic aluminum full-size tripod for still photos, with 90 degree flip feature for portrait mode, quick-release mount plate, and built-in level, will cost about twenty bucks and weigh about three pounds. It'll be nearly useless for video (too shaky, and won't pan or tilt smoothly enough), and tend to shake if you touch it or in high wind, but it'll get the job done for landscapes (use a timer or a remote shutter switch, and weight it down with bagged rocks in high wind). It'll fold up to about two feet long, which will fit on the outside of a summer backpack, albeit a bit awkwardly. Takes a few seconds to set up. Most can also be set up in an upside-down mode for flower close-ups, and changing modes only takes a few seconds. However, if you take a lot of photos while you hike along the trail, those seconds add up. My tripod mostly gathers dust unless I know I'll have a golden sunset opportunity.
Full-size means at least 60 inches. If I were shopping for a hiking tripod I'd take a serious look at a 50" or 40" tripod. (These are marketed for cell phones, but most include a photo screw head). They're cheaper, lighter, and best of all, pack smaller. Check listings carefully to make sure they're rated for your camera's weight (including lens) plus a healthy margin.
For wildlife photos with a great big lens you'll need a tall, extra-sturdy tripod, but for landscapes, a smaller tripod should work.
