It is difficult to get a visitor visa while a PR application is being processed. This partly depends on what country the applicant is from. It might be easier to get her a visitor visa before you send in the PR application, then send the application in right away after she arrives.
The visa officers look more at the applicant than the sponsor. Your wife must show proof she will leave Canada when her TRV expires. So your status as an employed professional will help show you can support her during her stay, she has to show more than this. She should have a return ticket with a specific date, ties to her home country such as a job, a house or apartment, enrollment in school, etc. Then she shows a letter from her boss giving her two weeks vacation (or whatever) and stating she is expected back, receipts showing she has paid for classes that start after her date of return, proof she has paid her rent for times after her date of return, things like that. Leaving a child behind is also good proof, if possible in her case I don't know. Evidence she has traveled to countries where she needs a visa before and returned on time can also help.
So there is no harm in trying for the TRV, but usually they are refused.
One or two attempts to enter Canada to see her boyfriend or spouse shouldn't hurt her PR application, thought they will have to be mentioned on the application and explained. What will hurt her PR app is many unsuccessful attempts to enter Canada and other Western countries.
