It could be that you're American. They treat Americans kinder than us "aliens".

I94 must be paid for with a credit card (if they have a machine) or AMERICAN cash ! they will take your picture and finger prints.
Make sure you have adequate medical insurance (just in case)
No fruits or meats of any kind with you so be careful what snacks you have in the car.
You will have a hard time getting back into Canada without your TWP which to be honest should be stapled into your passport.
I mentioned payment because very small border crossings may not have a credit card machine and they don't accept any other currency except american, ex trucker here who had to perpetually get I94's When you reach the canadian side when you come home you should ask them about surrendering your I94 if your not planning to return to the USA, if it runs out and it's not returned the next time you want one to go into the states they may refuse you. And make sure you have your TWP with you, i know a border guard personally and people have been refused entry without them which would then put you in quite a pickle.
When you go inside the building to get your I94 dont take your phone with you, they don't like any chance of being filmed etc. Its unlikely in a rental you'll have a dash cam but if you did then turn it off and remove it from the dash, they can get real upset if they think they are being filmed or recorded and you don't want to upset them USA border guards they can be quite mean. TV shows have permission to film, you do not.
Ive actually been there when an american was going home, they gave him a very hard time before they let him through, i asked him how come and he told me he has that every time because once they allow him back in they can't get him out which doesnt make sense but he said he used to it after years of crossing into and out of Canada.

When you are being processed for the I94 you will need to give the addess in Mt. Baker so have it handy.They used to ask if you were a member of the Nazi party but dont ask that now! They will ask you if you have been in trouble with the law or ever been arrested ,just answer no.

FIFY

Whatever pleases you.

What does FIFY mean ?

Fixed it for you !

I'd only answer no if no is the truthful answer. I wouldn't lie to a customs official.

True it could be. I don't have a way of experiencing entering as a foreign national.

I have always found the American immigration guys to be very friendly and pleasant. I always try to have a joke with them, and it has always worked, from the guy in Buffalo who hunted out a special stamp in the shape of a Buffalo for the boys' passports when they were small, to the guy who was really interested in the Second World War and wanted to hear all about my parents experiences living through it, to the guy who, after a mixup with four and fore fingers that I have posted before, waived the fee for the I94.

All entries into the United states do require secuirity checks prior to entry. Make sure u do have all necessary paper work before departure.

If you are crossing at a land border there is no paper work to do before departure.

Anything else useless that youd like to add?

When they scan your passport and/or put in your details in for Canada if you have a criminal record they can see it ! No pre check required just wasting your time attempting to cross with a record.
Although i have been arrested in the UK i ALWAYS declared that arrest when crossing as a truck driver, worst thing you can do is lie to them because if you do you won't be going stateside ever again.

Not every border crossing (in BC) does this - only the major border crossings. And if you enter via a ferry, I've never been charged the $6 bucks.

Can hardly wait 'til my EDL arrives then I won't have to worry about border crossings anymore.

I crossed as a trucker so i only used major crossings or maybe being a trucker i HAD to have an I90 ? Being from Winnipeg most i know who crossed in their cars crossed at Emerson which definitely is a major crossing and they always had to get one. I do know of one trucker caught with an outdated I90 and he was arrested and taken to jail for a week or two.