Bob
I do not have ride details of your first two that you posted. I believe those were posted in the book "Guide to South Florida Off-Road Bicycling" by Rob DeGraaf. My copy is an older one, but from a search still seems to be the current version. The books are available and inexpensive, so you might give it a look.
In regards to the long ride that heads North, that route can not be ridden as shown without jumping fences and riding where you are not allowed. On the Northbound stretch, it is only a legal ride to Arthur Marshall, or somewheres around Boynton Beach Blvd. If you do continue North, in Western Wellington, there is a pump station / spillway for the canal. It is fenced, posted and has no easy way around it. Additionally, once past the pump station and still heading North, I heard rumor a few weeks ago that they are not allowing hikers, cyclist or others to head east from the SR80 trailhead, this would be that section. This I have not confirmed yet, and doubt we will ride there anytime soon.
We have done the levee ride from Arthur Marshall south to Lox road and back.
Often on these rides, it's not so much the distance, but rather the strong winds of the everglades, the heat, or violent rain and lightning.
The one person that may have more details would be Stan at Wheels of Wellington. He should know all the legal or at least sections to the north where those 38's should do ok.
PK
PK, good advice. Thank you. I don't plan to do the northern 75 mi anytime soon, so I'll be sure to check it out.
BT