K-Country was established in 1977 by the Alberta government to provide an alternative to the crowded conditions experienced in Banff and Jasper.
One other really annoying thing about going to Banff is being awakened by the train whistles late at night and early morning hours. The mainline is right beside the Trans-Canada (#1) highway where all of Banff's formal campgrounds are accessed from.
Jasper is nowhere near as bad as Banff for crowds. You are more likely to see a bear in Jasper NP than in Banff NP. I have yet to encounter a bear on the trail in Banff NP although I have seen one run across the road.
A secondary vehicle access is via the Smith-Dorrien-Spray Trail from Canmore. As you leave Canmore, the road is initially paved but turns to gravel just past the Nordic Centre. This gravel road begins with a breath taking ascent up the eastern flank of Mount Rundle. Note that this road is extremely bumpy in many places and speed limits range from 35 to 80 km/h. On the sections marked 80, I usually do not drive faster than 75. You would be ill-advised to drive this road if you are in a hurry. Traffic is relatively light even in mid-summer but watch out for logging trucks.
The Spray Trail winds it way past the 3 Sisters Dam and Spray Lakes Reservoir and on for another 45-50 km before connecting to the Kananaskis Trail in Peter Lougheed Provincial Park. There are several day use areas along the way but the only commercial facilities are at Mt. Engadine Lodge.
The majority of camp sites (500+) are in six campgrounds contained within PLPP, 50km south of #1. Only two of these campgrounds, Boulton Creek and Elkwood, have showers. Reservations can only be made for Boulton Creek, the remainder are only available on a first come basis.
The Spray Lakes West campground is spread out across the western shore but you would be very lucky indeed to find a vacant spot along the scattered shore sites in July and August. The majority of sites are crammed together in a small area a few km past the dam. The area is within trees but the area is mostly devoid of good separating bushes and trees between sites. If you are planning to attempt the Big Sister (2936m), Mt. Nestor (2975m) or Mt. Sparrowhawk (3121m), it's a logical camp site location. I have only stayed there once (1996) to do Sparrowhawk and Big Sister (alas rain and snow prevented an attempt on the latter).
Firewood is available for sale at certain times of the day (usually 4 to 8 pm). In 2002, the cost was $5-6 CAD per bag. If you chop the wood into quarters or eights and have a moderate fire for 2-3 hours each night, two bags should last three days. Unlike the National Parks though, you do not have to buy a fire box permit (now $6 CAD/day!).
Further information on campgrounds can be found in the Alberta Campground Guide which you can pick up at any CAA office. You can also call Travel Alberta at (800) 661-8888.
The Kananaskis Camping web site has even better information on the campsites they operate, including maps and vacancy reports.
An excellent reference for finding suitable hiking trails can be found in the Kananaskis Country Trail Guide by Gillean Daffern. For scramblers, Scrambles in the Canadian Rockies by Alan Kane details routes for dozens of non-technical climbs in K-Country. Both books are published by Rocky Mountain Books of Calgary.
Also see the official Kananaskis Country web site for trail reports and other accomodations.