Rode this trail today. Newly paved and in great shape. Great bypass to Route 9W over the Hook Mountain "hump" with it's very limited shoulders and fast-moving cars and trucks.
There is a small unofficial parking area at the south end of Jones Point.
Just north of the northern end of the trail make a right onto the Iona Island Access Road. Interesting spot to check out with a bird sanctuary and some buildings that were once used as a military ammunition depot.

Cars don’t have to yield to bikers and it takes a while Otis cross multiple roads.

April 2021: Hadn't been on the trail a couple of years, hoped they had caught up on maintenance. No such luck. Long stretches full of cracks, bumps, sunken spots and washboarding. It was a teeth-rattling experience. Not recommended, esp. for road bikes.

Rode the Maybrook trail for the first time this morning starting in Brewster, going north. Lots of gradual uphill going north which made the return trip easier. Beautiful natural scenery.

Road this entire trail this past week as an out-and-back from Brewster. It's in perfect condition with limited road crossings.
As previous comments noted it's not exactly flat. Signage states you cross the Appalachian Mountains (known as the Taconics in this area)!
In Brewster I parked in Markel Memorial Park which is closer to the southern end than Southeast Town Park. It has a short road hop to an on-ramp to the Trailway.
If you want to take the older section to Connecticut the new Trailway dead ends at Peaceable Hill Rd with steps down to the road. There is an unmarked road section leading to another flight of steps on East Main Street (bypassing an unusable trestle). Note that the trail ends about a mile south of the steps where the trail is being reconstructed (no signs of activity).

Road from kintnersville to Erwinna. Beautiful scenery. Saw a muskrat, Ducks and turtles. Trail narrows at times. We went on a week day. I am sure the weekends with more people would become challenged at points. All gravel trail.

DO NOT TRY THIS TRAIL ON THE ALLEY POND SIDE. CLOSED

I rode this trail for the second time. The last time I rode it was almost 7 years ago. The surface is packed gravel and can be ridden with just about any type of bike. I rode my hybrid without any slippage. There are a few streets crossings but cars stopped for me each time. At the beginning of the trail in Long Valley, there are horse farms and in the last few miles before High Bridge, keep an eye out for the gnome homes. Much of the trail flanks the Raritan River. There are a few places along the way to get coffee or a snack. Great ride for all levels.

Someone is placing man-made objects to cause flat tires on the part of the trail between Newton and Lafayette. Have a spare tube on you just in case. Had to cut my ride short because of a flat caused by a plastic spiked ball placed right in the middle of the trail. Good trail for a mountain bike or a hybrid though. Will come back to complete it.