How much traffic does Crooked Lake get? What is the quickest route to get there? And is it a good point to cross over into Quetico for part of a trip?

Depends on when you go. Depends on where on the lake you want to be. No rangers on Crooked.

Crooked lake has a moderate amount of traffic, and it DOES have rangers as we have been checked there. I'm not sure why Old Salt would say that. Maybe he is saying that it would be safe to cross over in to Quetico illegally? I will give you the benefit of the doubt and assume that you have an RABC permit to allow you to cross over, a US passport to allow you to return to the US side, A Quetico yearly vehicle permit so you can be in Quetico legally without going through a ranger station if not camping and, of course, also assume that you would not be camping on the Canadian side as that would entail picking up an entry permit at Prairie portage or another ranger station the day of, or the day before entry in to Quetico, as well as passing through the specified lakes on your entry permit within a day or two of picking it up. You say "for part of a trip" which sounds like more than a day trip. I'm not sure how you are going to pull that off. Crooked lake is not an entry lake. It SOUNDS pretty suspicious to me. Why don't you elaborate on your plans a bit more.

In order to cross into Quetico on Crooked you have to meet with the rangers (to get your permit) at either Prairie Portage or Lac La Croix.

Banksiana: "In order to cross into Quetico on Crooked you have to meet with the rangers (to get your permit) at either Prairie Portage or Lac La Croix."

The problem with that is, what entry point would he use? He would have to make it to PP and pick up permit for lets say Basswood river as that is probably the closest, and then he would have to paddle the river going downstream within 1-2 days(as that is what is required by law) then what? Enter the BWCA on Crooked and then cross in to Quetico again? Makes no sense. I have to assume he is either not aware of the regulations or is planning to do it illegally. Old Salt's comment was disturbing.

For those disturbed, upset about my previous post, I was in a hurry when I posted it. I meant to say that there’s no ranger station on Crooked, meaning that it’s not a legal entry point into Quetico. I certainly am NOT advocating illegal border crossing.
Mea culpa.

Definitely not talking about entering Quetico illegally. I guess I was making some basic assumptions that were incorrect regarding entry into Quetico. My buddy and I are planning our second trip to the Boundary Waters, and we are interested in possibly venturing into Quetico for two or three days as a part of that trip. Last trip we spent some time on Iron Lake and we are interested in possibly spending a decent portion of our trip on Crooked this time around. This is all for next summer. So a better question would be how do people legally cross into Quetico from the Boundary Waters? I think I’ve read something about remote access passes before, but never talked to anyone who has done it.

That's a whole different ball game.
First you make a reservation online to enter Quetico at one of the five park ranger stations. For Crooked Lake it would probably be closest to use the Lac La Croix station. You will then need to get an RABC . This will allow you to cross legally into Canada without passing through a formal border crossing. You will need to apply for the RABC well in advance of the trip. I would allow a couple months at least.
With your park reservation and RABC in hand, you can now safely paddle to the ranger station and pay your permit fees and continue on into Quetico.

old_salt: "For those disturbed, upset about my previous post, I was in a hurry when I posted it. I meant to say that there’s no ranger station on Crooked, meaning that it’s not a legal entry point into Quetico. I certainly am NOT advocating illegal border crossing.
Mea culpa."

Thanks for clearing that up, Old Salt! It didn't seem like something you would be saying.

I have never done this, but believe it might work for day trips into Quetico. There are a lot of potential day trips from a US campsite on Crooked Lake and you could be fishing the Quetico side as well.

Quetico offers a seasonal day use pass that you can purchase online. You can also get your Ontario fishing license and Outdoor card online. Add to this the RABC permit. It's a lot of permit logistics for sure. The day use pass is for vehicle entry. You need to make sure it works for entering by canoe.