If you are on an inland application, it's best to send the OWP application with the PR application; otherwise you can send it before AIP and ask them to "add" it to the existing application file. If you wait until AIP, you need to apply back to CPC-V for the inland permit (since you don't want to leave Canada).
If you have an LMO or NAFTA qualified job, you can just go to the border to pick up your work permit. CBSA issues them in about 20 minutes plus queue time. If you are not a US citizen or PR, you can tell them you are flag poling and they will stamp the date on a piece of paper that says "administrative refusal" - a polite way of saying "here's a date stamped piece of paper to make CBSA happy". If you are a US citizen or PR, you must get your passport stamped, as you can't be refused. But that way you still have a piece of paper (your passport) date stamped. In either case, it shows you are "entering" Canada and thus can apply at the POE.