True Ottawa to Montreal is around 200 kms.

I checked Parliament webpage i am cutting & pasting info off their web page.

All visits to Parliament are offered free of charge. Tickets are available on a first-come, first-served basis. Groups of 10 people or more who wish to take a guided tour must reserve in advance. Individuals and groups with fewer than 10 people can get same-day tour tickets as of 9 a.m. daily.
From May 13 to September 1, tickets are available at 90 Wellington Street (across from Parliament Hill). From September 2 to May 12 tickets are distributed at the visitor entrance, at the base of the Peace Tower. Demand for guided tours is highest in the summer months, which may result in limited ticket availability. For information on guided tours and other visitor options, please see Visit.
Facilities Security


I am not too sure what are the odds of getting tickets for individual during summar months


All the above 5 places are close to each other.

I kind of concur with Yanksingh it would defiantly take more than a day to visit ottawa at your own pace.