It really depends on what else you want to do over the winter.
On Vancouver Island you can golf year round, Kayak - just dress for the weather, fish, hike, visit wineries, just about everything you can do in the summer. The days are just cooler, damper and shorter.
Snow is a rare thing and because many locals cannot drive well in it, it is best to avoid the roads. My son's university in Nanaimo closes if there is snow, because the campus is built on a hillside and there are stairs running up and down. They cannot keep the clear of snow and it is a safety concern.
Recent trip costs.
OP asked for recent trip costs for comparison.
DS and I drive to Saskatchewan from Vancouver Island at the beginning of June. We drove in the Santa Fe, spent a couple nights with family and three nights at a Monastery ($180 per night 3 meals included).
Other than the Monastery, we had 4 nights in motels (3 Travel Lodge, 1 Holiday Inn Suites) Hotel costs were $99.00 to $129.00 for the Travel Lodge with a free breakfast and $200.00 for the Holiday Inn. We did not prebook any of the accommodations. All were clean and comfortable.
It cost between $50.00 and $60.00 per tank of gas and we got 600 km per tank.
If we had taken Mobi (27 foot class C), the ferry would have cost $45.00 more each way. It costs over $100.00 to fill the fuel tank, but I only get a bit more than 300 km on a tank. So fuel costs would have been 4 times as much.
One last important point. The trip we took required long days of driving. I find it more tiring to drive a motor home than the Santa Fe. My son has not yet driven the motor home and he needs local experience before driving long distances on strange roads.
For this trip I think money spent was about the same. The increased fuel consumption balanced out against the hotel costs. The days at the Monastery were set and would not have changed even if we did have the motor home.
It was a holiday, eating out is part of the fun of travel. We did not eat a single meal in a chain restaurant. We did travel with lots of healthy snacks, water and juice.
We have done to trip to Calgary from home in the motor home several times when we had more time for our holiday.
You may have already been, but the Steelhead Provincial Park at the West End of Kamloops Lake at Savona is a beautiful small campground.
If it just off the Trans Canada Highway, so not good if you plan to take the Coquihalla.