From what we've been able to glean, most folks technically rent a room from a family member/friend to have as their official home base for officialdom requirements such as drivers license etc.
We are prepping to go from extended to FT within the next couple of years, and as far as we understand it, we have to be present in our province for 5 months per year to retain our health care. How they track your presence within the province I don't know.
If you are spending a large amount of time down in the USA then you should also look into whether/when necessary for you completing Form 8840 based on your previous 3 years presence = closer connection to home form courtesy of Uncle Sam.
www.travelwithkevinandruth.com These folks are a lovely frugal Canadian couple FT Rving general, as well other style of travellers for several years and may be a good source for you on specific Q's.
Others we personally know of are typically Snowbirds in the USA 5 to 6 months winters, and BC generally as a homebase, mainly due to the kinder climate for the shoulder months. However, there are some Northern AB and many other province folks that do full-time as well. AB will remain our homebase province when we FT.