I've ridden the Puyallup Riverwalk Trail on a handful of occasions. It's one leg of a 50 mile (century round trip, minimal elevation change) route between Seattle and Tacoma (from Tacoma River Rd to Puyallup Riverwalk Trail to Link/White River Trail to Interurban Trail to Duwamish Trail).
Along the western end of the trail, it travels between River Rd and the Puyallup river. The River Road trail-head does not have any marked parking, it shares space with a pull-off for a truck scale. Approaching this end of the trail via bicycle along River Road is OK, there's a paved right-of way on River Rd, but it's not particularly wide on the North side of the road, and there are intersections and businesses on the South side of the road (plus you then have to cross a busy 4-lane highway to reach the trail). Towards the West end of the trail there are side street with parking, as well as a Fred Meyer (no idea what their policy is on parking there to bike, but it appears some people do). In Puyallup, there's a gap in the trail with some parking at both ends of the gap as well as parking (decent lot plus on-street) at the East end of the trail.
Views/Connections (West to East):
From the West, it's pretty much River Rd. As mentioned this is OK. Views are decent. One side is the river, other side does have businesses/farms (not necessarily scenic ones) in the foreground and great Rainier views in the background on clear days. The mountain is effectively hidden from view once on the trail. There are spots to pull off for views of the river, which remains near the trail on one side. The other side is not as scenic. Several places there are Trees, a Berm/Levee, businesses and homes. Before you reach Puyallup it is still enjoyable from an ambiance perspective. As you reach Puyallup, there's a Fred Meyer, as well as bar next-to the trail (good refueling spot for those on longer rides). The Bike Rack at Fred Meyer is at the far end of the entrance, which does strike me as a little strange given the proximity to the trail. Up until the gap, you're pretty much in town with houses on one side and the river on the other. There is a gap with signage to reach the other portion of the trail. Overall I've never encountered significant traffic, so I would consider the gap to be reasonable. After the gap, even though the trail is in town, it is well isolated with river on one side and trees on the other.
The eastern portion of the trail continues East to East Main Street. Across the bridge on East Main can get you to the White River Trail (approx 1/8 mile on road), or go Under East Main to connect to the Foothills trail (one mile on road). There's also a gravel surface trail that continues along the river but I've never ridden it. There is a nice view of Mt. Rainier at the East end of the trail (after passing under E. Main).
They appear to still be working on portions, so condition is overall quite good. Not much elevation change, so it's a reasonably easy ride.