Teklanika ("Tek") River Campground is at mile 29 on the Denali Park Road. The second largest campground in Denali, it offers 53 sites for RVs and tents. It is open May 20—mid-September each year. You may tent camp at Tek, or camp with a vehicle / RV. If you do not have a vehicle, you will use a special type of bus called the camper bus to reach the campground. While you are at Teklanika, you can re-use your camper bus ticket to go sight-seeing west-bound (i.e., farther into the park) on any non-narrated transit bus (not just camper buses) during your stay. This is true whether you camp one night or a week (or longer) - your initial camper bus ticket lets you sight-see west of Tek during the entire stay. You cannot go east (i.e., back to the park entrance) until you are finished camping at Tek. This is also how tent-camping works at Wonder Lake, Igloo Creek and Sanctuary River Campgrounds. Unlike vehicle camping at Tek, tent campers at Tek have no minimum number of nights they must stay - you can just camp here one night if you wish.
Normally, park visitors cannot drive more than 15 miles into the park. Camping at Tek with a vehicle lets you break that rule, as you are allowed to drive 29 miles on Denali's only road. You may stop on your way to/from the campground to sight-see (e.g., you can park at a pull-off to take photos or go on a short hike); however, once you reach the campground, your vehicle must remain parked for the duration of your stay. In addition, camping at Tek with a vehicle requires a three-night minimum stay. To sight-see during your time at Tek, you'll be able to use the shuttle bus system, as long as you purchase a special kind of ticket, called the "Tek Pass." nps.gov/dena/planyourvisit/campground-tek.htm