Hi.
Canada/US travel is fairly easy; just check for what's not allowed.
Gas is a bit more than US -- lowest in our area is 90 cents/litre (about a quart) but it sells for 20 cents more at some stations.
Find out your rig's size in meters. I put the height in both systems on a tag on the rearview mirror -- you don't want to do conversions at 100 kph. Quick speed conversion: drop the last zero and multiply by 6.
Bring your passports if you want to go home again.
Be careful with Hwy 407/ETR around Toronto. Tolls are excessive and if you don't have a transponder they charge even more.
We found Boston a bit of a bother to get in and out of. Not sure if Cape Code can be done same day.
We use Liberty Harbor for NYC. Again, a pain getting into town but worth it.