I'd like to move our life forward a bit and head up to Canada and live with my wife at her home, working remotely for my company. Is this doable with an (outland) application in progress? Can I work for a US company as a visitor from within Canada?
Grey area. Are you planning on telling anybody? If you are not, it is not like anybody will find out.
Ideally I'd like to stay there for the entirety of the 6 months I'm allowed to stay as a visitor, which hopefully should line up with when I should hear a decision on my immigration application... can I be refused entry if I head up with this intention? (last thing I need is an IO saying I can't enter... after I cancel the lease on my apartment and close a bunch of accounts....)
You are not supposed to move to Canada on visitor status so if you show up with a u-haul with all your furniture in it, you are asking for trouble.
You have two options.
One is arriving, preferably with your wife, and stating that you are coming to stay and planning to apply for sponsorship and if you can get a visitor record to stay for longer than 6 months or at least get a passport stamp so you can apply for an extension later. In many cases they will let people in like that but if you catch an immigration officer in a bad mood, he may turn you away and say that he can not let you in as a visitor unless you are only coming temporarily and not to come back unless you have a letter from your employer stating that you have a job and must return to the US to work on date x.
The other option is come to Canada to visit but ask for a passport stamp as a souvenir. In most cases, they will not limit your time so you automatically get 6 months. After 5 months, you can apply to extend based on waiting for your sponsorship and that extension should be enough to stay until you get your PR. To be able to extend, you must have proof of when you entered, that is why you need a passport stamp.