Hiked this trail today and personally enjoyed it. To clear up some confusion that may occur there are a few different trails in the area with varying difficulties.

There are ~5 trails inside the actual park, estimated because they interconnect and you could hike more or less and create your own. They range from .25 - 1 mile in length. These trails, from what I saw of them, were paved and very well maintained, definitely an easy stroll.

There is also the sweet water spring loop trail, or Damian Maertens trail, not sure which came first and they are one and the same path. This trail is 4.8 miles in length with a few opportunities to shave some distance/time off. This is the trail that highlights when you select northwest trek trail. This trail is easy going for all but a mile of it, this mile is located between sweet water bridge and about 300 yards from the quick return .5 mile shortcut. Between these two points the trail is very narrow, loose soil in places, for a good portion it has a 65-75 (estimated but close) degree slope on one side and either a continuation of this or an electric fence on the other, with a couple hundred yard decent to the bottom. If you started the trail heading south, through the park entrance, you will have to climb in elevation through this area. We opted to start heading north at the trailhead and didn’t notice any significant change in elevation until we descended in this area. The remainder of the trail is very easy, capable of two people walking adjacent to each other comfortably.

Wildlife was scarce for our trip. Rabbits, chipmunks, lots of snails and slugs, and a few lizards/newts. There were a few picture worthy flora samples in the area. As you have read from other reviews nettles are abundant and present along the entire trail.

TL;DR: If you’re taking kids or inexperienced hikers I’d recommend paying the admission to the park and enjoying the well maintained paths and the scenery. If you want a little challenge, enjoy the sweet water spring loop, just keep an eye on the time as the signs state the trail gate is locked when the park closes.