Little Tupper to Inlet on the Oswegatchie River

I have a week off coming up, and I'm eyeing the Little Tupper Lake to Inlet on the Oswegatchie Traverse for my days off. I have both the Paddler's Map and the Adirondack Paddler's Guide which have tons of useful information, but figured I'd make a post here also soliciting additional information since most of this route is largely unexplored territory for me.

I'll probably have at least 7 days to devote to this trip, although from reading information about the route online, it sounds like even 5-6 days isn't super rushed. I'm thinking I may try to devote an extra day or two to the Oswegatchie River section specifically, both to snag a few lean-tos needed for the lean-to challenge, and to check out the numerous campsites on this stretch in preparation for a possible future trip with friends (our annual "Duck Hole" trip this year will likely be a paddling trip).

My tentative itinerary:

Day 1: Put in on Little Tupper. Will likely be somewhat later in the day (after car shuttling in the AM) so will probably just aim for a campsite on Little Tupper, perhaps on the southwest end of the lake. If early enough, I may push on to Rock Pond instead.

Day 2: Paddle/portage Rock Pond, Hardigan Pond, Little Salmon Lake, Lilypad Pond, Shingle Shanty Brook. Camp on Lake Lila.

Day 3: Paddle/portage Harrington Brook, Clear Pond, Bog Lake, Low's Lake. Camp on Lows Lake, possibly on Grass Pond (I remember the sites being really nice up there).

Day 4: Paddle/portage Deer Pond and the traverse to Oswegatchie. Camp somewhere on the upper Oswegatchie (possibly High Falls).

Day 5: Paddle the Oswegatchie. Camp somewhere on the middle Oswegatchie (possibly Cage Lake Springhole).

Day 6: Paddle the Oswegatchie. Camp somewhere on the lower Oswegatchie (possibly Griffin Rapids).

I can't find a definitive length for this route (and I'm too lazy to calculate it myself) but by rough estimate, it seems like it would clock in at roughly 50 miles, maybe a bit less.

My day 2 seems like it probably has the potential to be a bit longer- so I may try to shorten it (possibly at the expense of making Day 3 longer and forgoing Grass Pond). I'll probably also plan to carry 7 days worth of food with me so I can add another night somewhere if needed. Admittedly my last few days are super short, but again, one goal of this trip is to target lean-tos on the Oswegatchie River that I still need for the lean-to challenge. I've also already extensively hiked the trails in the High Falls/Five Ponds area but may do some day hikes from the river along this network to stretch my legs.

Time permitting I may also try to do a few side trips. I've done Fredrica Mountain before but wouldn't mind a return visit. I've also heard that Grass Pond Mountain is a worthwhile bushwhack.

A few specific questions:

• Are there any campsites along this route in particular that are particularly nice? I know some of the Low's Lake sites are really nice (and again, Grass Pond is one of my favorite spots to camp in the ADKs). But the sites on the stretch between Little Tupper and Lila are all new to me.
• How is the stretch between Lake Lila and Low's Lake? The Paddler's Guide makes it sound pretty straightforward but the St. Regis Canoe Outfitter's website says that the "portage to Harrington Brook is rough." I also know that the south end of Lows can get pretty muchy with low water levels and am anticipating some potential rough going there given how dry it's been this year.
• How are the rest of the portage trails generally? Has anyone paddled parts of this route recently and can comment on any major issues? The DEC's backcountry conditions page for the Western Adirondacks is... noticeably lacking in any sort of portage trail condition information for this entire route.
• Any other side trips along the way that might be worth doing?

Thanks in advance!