From Lipan Point to Tanner Beach at the Colorado River is nine miles and 4650 feet. This is the description of the first part of the trail from the NPS guide:

What remains of a once popular pioneer-era trail goes down the gully immediately east of Lipan Point. The upper section of the Tanner Trail is narrow, badly eroded, and can be difficult to follow, especially after a winter storm.The trail stays on the slopes east of the bottom of the gully through the Toroweap and switches to the west side at the top of the Coconino. Rock slides in the Coconino have covered the original trail in places, forcing hikers to improvise short sections. The trail descends steeply across the slope west of the bed of gully nearly all the way to the Seventyfive Mile Creek - Tanner Canyon saddle. A prime canyon view at the saddle is the reward for a couple of miles of notably insecure hiking.
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I think we dropped around 1700 feet from the rim to the saddle and we didn't have any problems following the trail (although yes, it was steep and narrow in spots). The saddle is really the first place that provides a comfortable break area, although we didn't stay long because it was in the shade and chilly. We had hiked down a side gully and the saddle was the first spot where we started to have some nice views of the larger canyon.