Oh boy, I can tell I have a lot to learn to try to get this done. I read your reply and just thought "Wow, he is going so far over my head here". 😉
I read everything at the link you provided and I reached a starting point of understanding what you're saying here. I don't fully grasp it, but I have a basic idea.
One thing I have to ask first here is, am I reading that page correctly in seeing that you can create new site content strictly from form responses using Toolset Forms? If so, a large lightbulb just illuminated over my head with newfound realization of the power provided here. Forgive my sidetrack thought here. I just have to say this is awesome if I'm understanding it correctly. I have many applications for this if that is now easily doable.
As it applies to my current question and your thoughts towards a solution, do we need where you said Events? We really only need Ride and Reserve for that Ride unless there is something to the process that requires the Rides to be under Events in how this is to be built. We're just trying to duplicate functionality from the registration plugin for The Events Calendar found in trying to create this exclusively with Toolset. But we do not need an Events content type. If we can succeed with setting up this Rides & Reserve system, we'll be deleting The Events Calendar and all the plugins that we installed with it because it won't be needed. So please just clarify if you suggested using Events because it is needed, or if you suggested using Events because I said we're using the Events Calendar.
So now I have to learn everything with Toolset forms, Parent Post and Child Posts, and Relationships. Am I understanding it correctly that this line that says:
"In the Parent post section, make sure to select the option Set the parent according to the currently displayed content."
That means that I can have one Registration Form that will create a new post of the Reserve content type and that I can designate that post to be a child and assign its parent to the current Ride that the Registration form is on? If I'm understanding that correctly, then that is completely awesome functionality. But it's still going to be a bit of effort on my part to wrap my head around it and how to set it up.
So for each Ride, we'll have say 20 Reserves. Will the parent Ride designation be within each Reserve? If so, then we can create a View that shows all Reserves, which will include Name, E-Mail Address and maybe Phone Number fields, and then filter that View to only show the Reserves for the current Parent Ride and then place that View on the Ride page for display, or maybe on a separate Ride Registrations page that would be an Admin only page. That would get us everything we need for people to register for each Ride. I will work on this as the first phase of my effort here.
Then the second phase would be to figure out how to take all addresses in the e-mail address field for Reserves and to allow a Ride Leader to bulk send a Notification to all Reserves. If that must be done manually, that will be OK. But if I can somehow set that functionality up within this system, that would be even better and might even exceed what we have with the current plugin. That would be spectacular.
Is it OK for me to continue in this thread and be able to pick your brain as I try to learn all this? Or at least what I called the first phase above?