Hey, we were just there last weekend!
Definitely important to know where in the park you'll be - that Tote Road is a long, slow drive.
Take all your water, all your food in coolers with 10lb block ice (Dead River Company gas station in Millinocket has it), and fill up the gas tank. Once in the park you don't leave. You can filter water, too, but I like to just bring in all I need.
No tents allowed at lean-to sites on the ground, but if you have an exclusive lean-to all to yourself, you can set it up inside as bug protection.
If driving to someplace within the parkfor day use, go early as many destinations have very few parking spaces available.
Kidney Pond and Daicey Pond both have canoe rentals and are definitely worth going out on. Go to the ranger station; last I checked they cost $1.
Doubletop is a wonderful peak to climb.
If in the Daicey Pond area, it's a beautiful walk along the AT southbound past the old Toll Dam, Little and Big Niagara Falls.
How huge a hike do you want? N Brother, S Brother, and Coe all together make a nice, big loop (go up the Coe slide; it's slab and not scary but make sure it's dry) and are all beautiful open summits. You can even bushwhack out to Fort and back for the extra NE100 peak, but now we're talking very long day.
All camping is at designated sites by reservation only. Check the regs at
http://www.baxterstateparkauthority.com
Don't bother with the Golden Road; just take I-95 to exit 244, then go west through Medway into Millinocket and continue, following the park signs. The road is paved all the way to the Togue Pond gatehouse.
It's spectacular!