would be the Google route from about I-89 and I-91.
From Lebanon, NH to Saguenay, QC it takes about 6h 30 min.
Is your current map USA only? Most of the US maps also have Canada on them.
You are not supplying a proper model number. Do you use the HOME or MyDrive software to update your device?
Test your device if it can go to Saguenay.
Use "Drive to City Center" (or proper destination).
You will now see NH somewhere at the right hand top.
Tap it and use the UP arrow to see if Canada shows above Colorado.
If yes, tap it, and enter the destination as always and you are ready to go.
Towards Quebec City and north of there road signs may (will) become unilingual French. Should not be a problem as, like in the States now, almost all are symbols.
Compass directions Nord/Est/Sud/Ouest are pretty apparent when you sound them out.