I haven't camped around there, but walked it several times. The village is at the bottom of steep forested slopes on either side - there's not many if any options on the way down, and while I've seen a couple of people camping on the way north (ie https://www.komoot.com/highlight/462206 ) , my preference if I was doing it would be to make sure I have all my supplies and then walk further, until the terrain levels out in the glen. But that means you can't pop down into the village for dinner or anything you've forgotten.
An advantage of doing this is that it evens the days out - instead of doing 9 miles Kingshouse to Kinlochleven, then 16 to Fort William, you can make it 12 and 13 or something.
If you'd rather camp close to the village, I suspect there are spots after you cross the river or if you cross the river and turn right, but not sure, and it's closer to houses than you should really camp.
Get a head net if you can. Weighs grams, saves sanity.
It's worth phoning the campsites - they don't put everything online.
I'm not sure what your plans are but you could look in to ordering from Amazon for delivery to accommodation or an Amazon locker. There's a locker near Drymen at Gartocharn, Alexandria, G83 8RX - it's a detour from the WHW. Amazon sell jet boil canisters at twice what you should be paying but it may be your only option: https://www.amazon.co.uk/Jetboil-Jetpower-propane-canister-heater/dp/B082YF3KT1/ref=sr_1_15?crid=76FA9ED2O7O3&keywords=gas+canister&qid=1652532591&sprefix=gas+canister%2Caps%2C115&sr=8-15
Not a guide book, but for your maps I highly recommend the Harvey long distance trail weather proof map. Trust me when I say, if it’s pouring down rain, you won’t want to pull out your nice guidebook to look at the map. I used this same brand for the Southern Upland Way and it never failed me. I own the WHW one and have been using it to plan my journey this summer. Really high quality material and weather proof map.
West Highland Way https://www.amazon.com/dp/1851372237/ref=cm_sw_r_cp_api_glt_i_HQ59RJPE6YV2HEG11KWA