Congratulations on your US VISA!!
Yes you may enter Canada with your Blue Travel Document and this is what proves that you have the right to enter the country.
I have travelled by car many times and when you cross the border they will ask you for ID, you give them the Travel Document.
They then can ask you questions as follow:
- where did you go in the US and what was the purpose of your visit?
how long were you away from Canada?
where do you live?
when did you make refugee claim and from what country?
did you already apply for your PR? you may also carry proof that you did.. such as the letter of receipt from Immigration Canada.
they may even ask sometimes: have you had any problems with CBSA before.. this will be due to your status being protected person and for some reason this brings up a red flag to them and pokes this question. First please tell them if you have had any issues OR THAT YOU HAVE NOT. But just also add that you were a protected person or that you claimed refugee status. (one of the officers advised me to say so a few weeks ago when I travelled; she says this makes it clearer for them). Given you're carrying a blue travel Doc I don't think this will be a time consuming question.
lastly, they'll ask you: what are you bringing to Canada ie. alcohol, gifts, weapons.
They may also ask to inspect your car (trunk or inside if it's a van) if they want to.
So far I've honestly had an excellent experience crossing the border.