British Columbia #6, 23 & 31A

The New Denver campground will look a lot like a ghost town after labour day weekend, as will most of the campgrounds after that last long weekend of the season.
Some campgrounds start shutting down right after labour day weekend, and 99% of them will be closed by the end of the month. ( in the West Kootenays)
Soup.

We did our first loop in this area in June 12 years ago. It was rainy and windy when we camped at the Nakusp hot springs - enough so that I had problems keeping the dining fly up. But soaking in the hot pool at dusk with a light drizzle and clouds shrouding the mountains made up for that.

On a later trip, we did a dusk soak at Miette Hot Springs in Jasper, and had a curvy 17km drive in the dark back to the Pocahontas campground by the highway.

The only free hot springs that I've used in BC is Lussier Hotsprings on the way into White Swan Prov. Park. That's right of a gravel logging road. The only clothing-optional springs that we've used were in remote parts of Idaho and Oregon.

Took #6 East from Vernon with 5er in tow. All was fine until we got to the top and started down. White knuckle time! :( Speed limits say 20k approaching turns (sharp nasty downhill turns)--you better believe those speed limits! Unless your rig has wings for when you can't slow down in time and go flying. We made it, but did not like that at all.

I think it would be ok coming the other way up that hill.

Once down, we did stay at Edgewood and liked that very much. (Hint, do not drive out on the sand! Don't ask.)

The ferry wait is on a steep hill so had to stay in the truck quite a while with foot on the brake. It wasn't going to hold just on parking brake and being in Park IMO.

When you get to the other side off the ferry, you are supposed to check out the mushroom burgers at the café that is right there. They are good! (Soup said not to miss those burgers :) )

This is a September trip. Leaving on the 1st & we have until the snow flies to get home but thinking 4-6 weeks.

The #3 is just too winding & hilly to use as a return route but if you know something I don't I'd be open to ideas.

#6 from Needles to Lumby is hilly and twisty but we towed a 28 ft fifth wheel over it with no problem.

You limiting your access and egress from the area by not using Hwy 3. Are you planing on driving back the way you came to the West Kootenays or do you have some other plan after the Hot Spring Tour?
Coming down from Revelstoke is pretty flat except for the ferry ramps. Not ant huge hills to speak of a good paved Hwy. Halcyon Hot Springs is about 10 minutes from the ferry landing ( east side Upper Arrow Lakes) they have a campground which is pretty basic gravel sites.
Nakusp is 30/45 minutes from the Ferry landing, on the east side. Nakusp Hot Springs are about 15/20 drive up the Side paved road from Nakusp. You will see the signs as you come into town from the ferry. They have a campground up at the Nakusp Hot Springs, but I always find the sun goes down to early in that tight valley and a constant roar from the creek plus the cool breeze from the creek, which is right beside the campground isn’t to my liking. The Hot Springs however are our of the ones around our area. You can get a snack at the Hot Springs, and bottles water/ pop, but that’s about it. If you plan on camping up there make sure you come fully stocked.
There is also Halfway Hot Springs ( halfway river ) but the Govt decides to put campsites up there and the wrecked the place, not many of us locals go there anymore. There is also St. Leon Hot Springs, but again getting way to popular and people abusing the area with garbage etc.... we no longer go there either.
But to each there own, some people can look past that stuff, I can’t.
Answorth Hot Springs was taken over a few years back by new owners and I have heard mixed reviews about it. Brother and Sister in-law were there at Xmas and found everything OK.
When are you planing to do this trip?
If it is before summer ( before July long weekend) I would recommend staying at the community campground in New Denver which is right on the shores of Slocan Lake. They do have limited reservations, but if your there before summer you shouldn’t have a problem getting a lakeside site they also don’t have hookups.but do have potable water and a dump station.
http://newdenver.ca/campground-2/

I would drive over from New Denver to Ainsworth in you car more flexibility for touring up to Sandon and the Dry Docked Paddle Wheeler Moyie in Kaslo.
South of Nakusp is Burton and it has a nice community campground on the shores of the Arrow Lakes and new washrooms a few years old ( buddy built them) dirt road small sign, no issue for a class A. It looks like you driving to someone yard as you leave the Hwy, but it is the road to the lake and campground which you can easily see as you turn onto the road.
The road from Nakusp to Vernon ( Hwy 6) is windy but not an issue in my old truck and 5th Wheel. If you take that route in or out of the West Kootenays take the short side trip down to Edgewood. Our fav hidden campground in Edgewood. Big sites... 3 of them up top. Side road down to the other sites is not Class A friendly. Outhouse and water available. It’s only a 15 minutes side trip off Hwy 6 even if you don’t stay, cool little town, one store that has everything including fuel.
Have fun
Soup.

OK no Hwy3,

Hwy 7 to Hope, Hwy 5 (Coquihalla) to Merritt (good CG called Kentucky Alleyne on Hwy 5a just south of Aspen Grove. Hwy 97C to Kelowna. Hwy 97 or Westside Rd to Vernon. Vernon to Revelstoke via Sicamous.
Visit a hot spring that you did not list, Canyon Hot Springs 35 km east of Revelstoke on Hwy 1,
Good lakeside CG on Hwy 23 north of Revelstoke (Martha Creek).

From Revelstoke Hwy 23 south to Nakusp via Halcyon. Don't be tempted to take Hwy 31 via Trout Lake to Ainsworth, it is narrow and twisty in places and much of it is gravel as far as Meadow Creek. Nakusp to Kaslo on Hwys 23 and 31a, Good CGs at Summit lake, Hwy 31 south to Ainsworth. Good CG near Balfour (Birch Grove).

Return on Hwy 3a & 6 to Nakusp, then south on Hwy 6 to Vernon (good lakeside CGs at MacDonald and Burton. Vernon to Kelowna and on to Aspen Grove. Here I would personally take Hwy 5a to Princeton, but that would force you to take Hwy 3 !!!

Moved to RVing in Canada

How late in spring are you planning to travel? 6 can have snow until mid May, it is not a fun drive in winter conditions. Believe me, I have done it.
23 is a much easier run although Kelowna to Revelstoke is an additional 2-1/2 hours. Nakusp south is good roads although be aware of a steep drop on 31A north of Kaslo, keep the speed down, don't ride the brakes and you will be fine.

There is a separate Canada section.

BC6 does have a pass (1300m). Maybe not quite as high as 3, but not too different.

BC23 is lake side. The drive from Nakusp to its hotsprings is a lesser road, with more curves and grades. Still RVs do drive it and camp at the springs.

BC31A also crosses a pass, but it's pretty low and gentle. (BC31 past Trout Lake is mostly gravel).