Being an outdoors enthusiast these days practically requires a degree in advance planning.

Oh, sure, there is still some room for spontaneity. But more and more, the most popular campgrounds and trailheads are booked months in advance.

So if you have any desire to roast marshmallows this summer under Half Dome's shadow or hike to the summit of Mount Whitney, now's the time to get your ducks in a row.

Here are some things you can do now (or soon) to make summer all the more memorable:

Yosemite

Campsites in Yosemite National Park are notoriously hard to get. In fact, they typically sell out in minutes -- or even seconds -- after they're made available online.

Seven of Yosemite's 13 campgrounds are on a reservation system operated through the National Recreation Reservation System at recreation.gov. These sites become available in one-month blocks five months in advance on the 15th of the month at 7 a.m.

What does that mean for this summer? It means Tuesday (Jan. 15) is the first day to make reservations for May 15 to June 14. On Feb. 15, reservations can be made from June 15 to July 14. And so on.

Phone reservations can also be made at (877) 444-6677, but using the Internet is faster since you don't risk having to wait for an operator while all the lines are busy. To save precious seconds on the 15th, log on before 7 a.m. and fill out a recreation.gov profile.

Between April and September, reservations are pretty much essential for all Yosemite campgrounds. The park also operates seven first-come, first-served campgrounds -- six of them are outside the Valley -- but even these typically fill up by noon during the busiest months.

Wilderness permits, required for all overnight stays in the backcountry, are available up to 24 weeks in advance. And, yes, the most popular trailheads fill up quickly.

Yosemite's hotels, lodges and tent cabins are operated through DNC Parks & Resorts. Go to yosemitepark.com or call (801) 559-4884 for details.

Last week, park officials set permanent hiking limits for Half Dome. Applications will be accepted March 1 to 31 on recreation.gov for the preseason lottery in mid-April. A secondary lottery also will be held during the hiking season for any cancelled or leftover permits.

Sequoia & Kings Canyon

Campsites in Sequoia and Kings Canyon National Parks aren't as impacted as those in Yosemite. But the busiest, including Lodgepole and Dorst Creek, are available six months in advance of the day you wish to camp at recreation.gov or (877) 444-6777. So that means you can make reservations today for all dates through July 10.

Other campgrounds, including those in Grant Grove and Cedar Grove, are first-come, first-served. (Campgrounds in Cedar Grove seldom fill up, even during busy summer weekends.)

Wilderness permits for the 2013 quota period (May 24 to Sept. 24) become available March 1.

Now's also the time to make reservations for the Bearpaw High Sierra Camp, an 11.5-mile hike from Crescent Meadow along the High Sierra Trail. Go to visitsequoia.com or call (866) 807-3598 for details.

National forests

Campgrounds in the Sierra National Forest and Sequoia National Forest/Giant Sequoia National Monument can be reserved up to six months in advance of your arrival date at recreation.gov or (877) 444-6777.

This means now's the time to reserve a campsite for your early July trip to Huntington Lake, Bass Lake, Mono Hot Springs or Stony Creek.

-- Sequoia National Forest also has two historic cabins and a fire lookout that are sometimes available for rental. Details: fs.usda.gov/sequoia.

State parks

California's most popular beach campgrounds, including those near Santa Cruz and Pismo Beach, are in high demand and often sell out minutes after they become available.

Reservations are available up to seven months in advance at 8 a.m. on the first of each month at reserveamerica.com. So that means campsites can already be reserved for July. For August, they come available Feb. 1.

Telephone reservations are also accepted at (800) 444-7275. Details: parks.ca.gov.

Mount Whitney

Hiking to the summit of the highest peak in the lower 48 between May 1 and Nov. 1 requires a permit. Yes, this even applies to day hikers willing and able to make the 21-mile round trip from Whitney Portal.

Due to high demand, the Inyo National Forest has implemented a lottery system through recreation.gov. Applications will be accepted Feb. 1 to March 15, and you can request multiple dates. (They won't appear on the site until Feb. 1.) On April 1, any remaining space will be open to online reservations.

The first weekend of August is typically the most requested date. To have a better chance of getting a permit, pick a midweek day in July or September. Details: fs.usda.gov/inyo or (760) 876-6222.