I also recommend TextNow as an option as @hairbag1 suggested, as they give you a new Canadian number you can call forward your Public Mobile line to. Then, you can continue to receive calls via TextNow over Wi-Fi or mobile data provided through a SIM card/mobile network in the country you are visiting.
Keep in mind though that since you are travelling to the USA, call forwarding will stop working if you let your phone register to a USA tower, so I recommend you physically remove the Public Mobile SIM from your phone while using the Mint mobile service to ensure it doesn't accidentally do so.
A nicety of TextNow would be that even if you don't manage to answer a call to your TextNow number, or the call came when you had no or spotty Internet service, you can still receive the voicemail notification once you do get back online.
If you don't forward, you can still occasionally check your voicemail messages by calling one of the numbers on this list I collected/developed a while back of all of the known Public Moible (and Telus & Koodo) voicemail access numbers across Canada: https://productioncommunity.publicmobile.ca/t5/Get-Support/Updated-list-of-Voicemail-Access-Numbers/...
Another option is to signup for a free YouMail account, and forward to the local Canadian voicemail deposit number they give you in your instructions. They will also email you notifications of new voicemails which you can listen to from the link in the email without even having to install their app, or get a few more features and text transcription if you do...
