I followed the instructions in the AMC guide, which leads to the Red Trail. The route in from the state highway—which is marked with white signs—goes from very good gravel to less good gravel to some very rocky gravel. That last part can be challenging to drive; take it slow. I parked at the gravel pit, and one walks down a dirt road. Make sure you turn right on the Red Trail; the Lower Red Trail intersects this road just before the right turn up the Upper Red Trail, and it goes away from the summit. I messed up on this, realized my mistake, and had to turn around. I found it a harder climb than other descriptions I read. The trail is overgrown and narrow, quite rooty in the lower half, and pretty steep. There are not many level sections. The red blazes do make the trail pretty easy to follow. An upended tree posed a challenge, but not an insurmountable one. Near the summit, the Red Trail joins the Blue Trail, which is billed as the most difficult of the three trails to the summit. The other, the Green Trail, only joins at the summit. The views are narrow, but there is a nice partial view of Moosehead Lake. A short ways down the Green Trail, there is a spot through which one can glimpse Mt. Kineo.
An interesting feature at the summit: in a stone ring, there are two plastic jars. One has previous hike logs and the other holds the current one.
Weather conditions were ideal for my early June hike. Other than the opening dirt road section, almost all of the trail is in shade until the summit.