In the end most places you need not talk to ATC if VFR. In southern airspace, which is where you will almost certainly be,(Northern doesn't start until you are way,way north) as long as you are below 12,500 feet which is also likely you can avoid talking to anybody until (a) you want to enter a control zone with a tower(could be class c or d airspace but who cares). (b) you want to enter what the class c or d airspace around the busier control zones such as Toronto and even less busy control zones such as Ottawa sometimes called TCA(terminal contol area). (c) busier airports with no control tower such as Fort McMurray but will have what is called a mandatory frequency(and usually a flight service station to talk to).
At most airports, there could be a NORDO aircraft legally flying there. I'm not sure if you are legally required to make an advisory for operating at one of these airports if you have a working radio. I just do that anyways. Many have a frequency designated(if they don't, you are supposed to use 123.2) In the end 90% of your cross-country flight or more can be without talking to anybody. However, you may want to request flight following. Workload permitting(I've never been refused) the controller will, but you may eventually run out of radar coverage. Then you are on your own.