Klahanie Campground is located on Hwy 99 “Sea to Sky highway” halfway between Whistler and Vancouver. Just 5 minutes south of Squamish in British Columbia.
Klahanie Campground has around 100 sites of various sizes. Some sites are suitable for RVs and have partial hook-ups (no sewer).
Some sites are more geared for tents.
Additionally, some sites may have a view of Howe Sound and others a view of waterfalls. 
The rates vary considerably depending on the site type that you get. For example: a tent site with no services for a mid-week stay would cost $48CAD per night compared to a premium power/water site with an ocean view booked for a summer weekend that would cost $95 CAD per night.
Site Review:
The quality of the sites is generally good. There is a gravel pad for most of the RV sites.
Some levelling will be required.
Access to the sites is a different story. The bigger the equipment the harder it will be to navigate the dirt roads and manage the site angles. Big rigs like the Class A motorhomes or the fifth wheel trailers would have a difficult time and may not be accommodated. If you have large equipment I would confirm prior to booking that it can be handled.
The Klahanie campground is directly beside the Sea to Sky highway. This is handy but you WILL hear traffic noise. There is also a train nearby. You will hear that too.
All sites come with a picnic table and fire ring. Wood is available for purchase where you check in. Should note that fire bans are frequent and outdoor fires may not be permitted during your stay.
There are washroom facilities with flush toilets.
The Shower Situation at Klahanie Campground:
There are showers available. You will have to pay to use them. 
There are a couple showers in the main comfort station, and also some located in the “shower house” located near the garbage dumpsters.
The cost for the shower is $2 for 4 minutes. Quarters, loonies and toonies are accepted. If you do not have the change there is a change machine directly behind the hut where you check-in. 
I would not necessarily count on it being operational, to be on the safe side I would make sure I bring my own coins.
RV Sanitation Dump Station
Klahanie Campground does NOT have an RV dump station. I have reviewed a lot of campgrounds and rarely do I come across one that accommodates RVs but does not have dump facilities by way of either sewer hook-ups or some kind of sani-station located within the park.
There is a free to use RV dump station located in the Canadian Tire parking lot in Squamish. (There is no potable water there though).
To access the dump drain is easy,
but be prepared for some long wait lines depending on when you go.
Activities:
Klahanie Campground is what I refer to as a “lodging only” campground. There are no activities within the campground to enjoy. There are no hiking trails or access to Howe Sound from the park. The camp roads are gravel and hilly and not particularly suited for biking. They don’t even have a playground (fortunately there is one in Squamish at the Squamish Oceanfront Park).
There are, however, activities to enjoy nearby.
Shannon Falls
Shannon Falls Provincial Park is directly across from the campground. You can see the falls from some of the sites within the park. 
but it is better to hike or drive over, and get a closer look.
Sea to Sky Gondola
You can hike 600m from Shannon Falls to the Sea to Sky Gondola. 
Or you can drive. There is limited parking at both places.
The Sea to Sky Gondola goes up (and down) the side of a mountain affording brilliant views of Howe Sound and the surrounding area. Each gondola has a maximum of 8 passengers so you are not overcrowded as you take in the scenery and enjoy the ride.
Once at the top, you can enjoy the walking trails, a gift shop, a small restaurant and a 100m suspension bridge, giving you even more breathtaking views.
Alice Lake Provincial Park
Alice Lake Provincial Park is less than 20 km from Klahanie Campground. There is a lake for swimming.
There are also canoe and kayak rentals available. You can use the Day Use facilities for free but you should note that if you are travelling with a pet, they are NOT allowed on the Alice Lake Trail, beaches, the playground, or in the picnic areas.
The campground itself has 96 sites, 55 of which have electric hook-ups. You absolutely must make reservations (and good luck with that) if you want to camp here. The campground gets completely booked as soon as the reservation window opens up.
Stawamus Chief Park
Stawamus Chief Park protects the 700-metre granite cliffs that stand at the southern entrance to Squamish on the Sea to Sky Highway.
The park provides rock-climbing opportunities of international significance. Hiking trails to The Chief’s three summits offer rewarding views of Howe Sound, Squamish, and the surrounding mountains. 
Whistler
The resort town of Whistler is about an hour’s drive from Klahanie Campground. Whistler is a world-class vacation destination. There are many all-season activities to enjoy and the facilities are top-notch. It is great for a day trip. There are lots of restaurants, and hiking and biking options. You can enjoy Lost Lake for swimming and paddling. There are museums and cultural centres. There are specialty tours as well. You can customize your day to your interests. 
Things to Know:
- Pets are permitted but must be kept on a leash and cleaned up after. You will be required to pay $5 per day per pet if you are camping with a pet.
- There are a lot of infractions that you can be fined for. These would include but are not limited to- too many people on your site, not properly stowing food and cooking units, being untidy, not sorting your garbage properly etc. You should familiarize yourself with the rules before coming because it is my understanding that they will not hesitate to charge your credit card as they see fit.
- There are no laundry facilities or trailer dump station.
- In my opinion, the extra money that you pay for a premium site is not worth it, with the possible exception of site #100 (it is the best site in the park).
- If you get a site with a water hook-up, know that the water pressure is very low- not much more than a thin stream.
IMO:
As a general rule, I don’t like private campgrounds. Give me a national, state or provincial park any day over a privately owned campground. I usually find that the owners of a private campground are spread pretty thin and often things fall into disrepair and the campground can be kind of run down and dated. That’s the case with Klahanie Campground. Another thing I don’t like about private campgrounds is the tendency to have the sites so close together that you feel like you are camping in a parking lot. I get it- space is money. Fortunately, there is good space between the sites here, so the parking lot effect is not applicable.
You have no amenities to enjoy in the campground itself, but you are in the midst of a very beautiful area and if you come prepared to venture out there are lots of activities you can partake in.
It’s not cheap to camp here. The extra fees for dogs, additional people, showers, and a campsite view all add up. There is only one site with an exceptional view of Howe Sound which may be worth spending extra for but there are several other sites that charge $30-$40 extra for what amounts to an obstructed view of rapids, or a partial view of the waterfalls across the highway that are not worth the money. It all seems excessive actually.
There are other campgrounds in the area and while the prices are around the same (except for Alice Lake -but getting a reservation there is almost impossible) they have more amenities, so you are getting more bang for your buck- like free hot showers and full hookups.
I would not recommend Klahanie Campground as an RV Place To Go.