Did the Allagash from Churchill Dam on down last week. It is a changed river since the 1980's when there was a good deal of logging going on due to the spruce budworm. Now there are few people working in the woods and some of the roads have all but disappeared.
I have several contacts with guides. I would suggest Sean Lizzotte of Allagash Guide Service in Allagash Village or Norm L'Italien of Pelletier's Campground in St. Francis to drive you and your gear in. Its about $200 per trip, so the more people you can bring the better the rate. You can drive your own vehicle in but it should be four wheel drive with a spare gas can and two spare tires and. Windshield damage is likely; you should have insurance for that. The outfitters will collect your car and have it waiting for you at Allagsh Village at the take out or come and retreive you and give you a ride to their compounds where you will find your car. The parking charge at the take out is $1 per stay.
Business is slowing down; seems families are not getting out. Many many campsites and usually there is no competition at all.
You can get a detailed map from North Maine Woods.
The portage around Churchill is vehicle assisted. Its $10 a  load. If you at least dont have the ranger take your gear, its foolhardy to risk losing it in the rapids and the ranger will have a heart to heart with  you. You can run Chase empty and pick up your gear five miles later at Bissonnette Bridge, where the ranger will have it waiting. Chase is Class 2, last week we had a minimal dam opening raising the water level only 250 cfs, so there was a fair amount of rockdodging. I have done it with kids; whether they will like it depends on how they and you feel toward the challenge. Its a rapid-pool-rapid-pool combination making getting swamped a less risky deal.
Round Pond Rips is a Class 2 also but shorter(no portage); the remainder is class 1 and 2.  All you need to do for safe passage is to be awake.At some water levels, you will have to stand in the boat to find the best channel. We did it at 1600 cfs, a very good level, moving most rocks buried and no dragging. Anything under 800 cfs is going to be dragging some and looking for the right channel.
Allagash Falls is a mandatory portage. Its 400 m all level or downhill with a very good pathway. Great swimming or lunch place with five campsites. Get out where the sign tells you to, dont press closer to the falls because there have been fatalities and injuries (its 40 feet tall).
You will most likely see a logging truck (they carry 230,000 lbs of wood, beware) at the Round Pond Bridge and Umsaskis Bridge(perhaps).
We did the trip Churchill Dam down in five very leisurely days. Last year my husband and I did the whole 98 miles in four days.
Its generally suggested for 7-10 days to do the whole waterway. The plus for the longer trip is seeing the locomotives and the entire railroad set up (boxcars, track etc) in the woods off Eagle Lake..the kids would love this.
Last year I saw four people; this year I saw(except for our group) five. Havent been to BWCAW in years due to overpopulation near the entry points so its hard to compare.
You will see moose(45 last year, 30 this year) and have very good prospects of seeing bear(they are shy; we saw two--the hind end mostly) and we saw lynx too plus a LOT of snowshoe hare(they hang out at the campsites). The campsites are for the most part grass covered and beautiful. There are rangers who take care of them; three along the river.They are also a neat source of information on the changes in the North Maine Woods.
I think that there is more of a wilderness feel here since its a long way south to population centers; even a town of any size (Millinocket ) is 150 miles south and you can go 150 miles west and still woods. Nearest town for services is Ft. Kent (pop 5000 about) its 30 miles from the end of the waterway and 130 from the start. There are no stores to buy canoe equipment like ELy ,beware. Rentals can be had from the outfitter.
Hope you come est!