Wondering if permitting allows a trip starting in the BWCA and then paddling into Quetico? Have not called the park office yet, but wondering if anyone has insights. I am guessing it will require a stop at a ranger station.

You still have to have a Q permit, available the day before or day of entering, from a ranger station, including the office in Atikokan. Probably means being at LLC, PP or Cache the day of, or before, entry. Unlike the BWCA, you can wander in and out of Q, so long as you have a valid permit while in. You could stop at a ranger station and pick up a permit and actually enter a few days later, as long as you're fine paying for all those nights. They're happy for the money.

The BWCA is a little harder since, according to what the USFS has told me, you need a valid permit when in the BWCA, and leaving it makes the permit invalid. Easy to carry a day paddle self-issue for a return without camping. Tougher if camping - EP71 permit.

Border crossing and fishing a whole other issue.

What Bill said.

I may add that crossing the border into Q isn't just crossing the border into Q. You're leaving the United States and entering Canada, a foreign country. You'll need appropriate paperwork (RABC permit) to legally enter Canada, along with passport to legally re-enter the USA. Legally re-entering the USA requires a stop at US Customs. All possible to do without too much extra work, but it's all part of the legalities of doing what you hope to be able to do.

I would agree with one exception. I think you are required by Park rules to enter Quetico on the day of your permit only. You are limited to getting your permit to the day before so in effect you can't enter when you want, like a few days later. Not saying it isn't done on the other hand.
You can also have certain outfitters (Quetico 100 outfitters) pick up your permit for you, at least at PP. It does give you some options. I have done this on a number of trips to the Q and found it useful.
If your arrangement is at all unusual it is pretty easy to get the Park HQ to bless what you are doing and to have them contact PP to tell them it is okay.

Thanks all for your input. Sounds much easier to just plan a Quetico trip from the outset. May try the nym lake entry this year.

The new superintendent at last year's Canoecopia told me the Q100 program is terminated. You have to have a face to face with a ranger to enter. I think there were two outfitters on north side who had a year or two longer to get permits for their customers.

I believe GC is correct that even if you pick it up the day before, you can't enter till date. You don't have to enter then, but that is earliest. Or so says the office.