What route are you taking specifically? Are you following the Route Verte network? Quebec City to Montreal is fairly straight forward, but there are several ways to get from Montreal to Ottawa depending on the kind of riding you like. The Route verte only shows the Quebec side of the Ottawa river, but cycling along highway 342 from Vaudreuil to Rigaud is decent as well. From Rigaud, you can ride across Eastern Ontario using very quiet county roads or a 60-mile stone dust rail trail that takes you straight into Ottawa. Click for maps of Prescott-Russell
If you are taking the Route verte via Montebello, it is quite interesting but you will be riding mostly along the shoulders of a somewhat busy secondary highway (the freeway bypass isn't scheduled to be completed until later this year). Oka (monastery and uniquely Canadian cheese) and Montebello (peek into the Chateau Montebello's massive log atrium) are certainly worth a stop if you are heading down this direction. My preference for getting into Ottawa on this route would be to take the ferry at Masson QC to Cumberland ON, ride Old Montreal Road to Trim Rd and turn towards the river to hook up with the scenic pathway that leads directly into downtown. Let me know if you need more specific information about Ottawa. If you turn on the cycling layer on Google maps, the extensive network of paved recreational pathways shows up and does a decent job of routing you through the city.