Not sure which forum this should go in sorry but it's only a quick question...

Travelling from the UK to Vancouver, then the following day onto Alaska, after 5 days we go back to Vancouver for a week and finally down to seattle by train for 2 days before getting our flight back to the UK...

My question is, is there anything I should ask for or say at the border as we're entering and leaving the USA/Canada twice in a short space of time? Apparently there's something the USA can give you that you keep for your journey I've been told?

Just want to keep everything as speedy as possible? We have ESTAs already sorted of course, I've been to the USA on this ESTA twice now, getting my moneys worth

Just tell the truth.

Lol, I hadn't planned on lying, just wondering if there's any kind of visa or something I should specifically ask for at the border?

There used to be a paper I94 that use could use for back and forth but now it is not used when flying. You will be fine with your plan.

When you fly out of YVR for Alaska, you will pre-clear US customs at YVR, thereby arriving in Alaska as a 'domestic' flight. I would suggest you explain your itinerary to them (as previously mentioned the truth is always the best option).

Crossing the border on the train is another story. Never done that, sorry.

Of note, though. Some countries require an I94 waiver. I am not sure if this applies to you (green paper to be put in your passport) It costs $6 or $9. You must give it back to Canadian Customs when you leave the UK, even if it is valid for 90 days. When crossing at land borders, they will often ask you if you plan on returning to the US before it expires and leave it in the passport (to save you the money). Airport customs agents are far more strict against this policy and if you go through US customs at an airport in Canada with the green paper still in your passport you can get scolded. If you haven't turned it back before it expires (as proof you have left the US) the you can be in trouble.