Yeah, it can take a little while to get all the terms figured out - and since they are pretty different things, it makes a big difference in the suggestions you'll get.
So, the time off requests - is this repeating data in your form? Or is it flat (i.e., one request per form)?
If it is flat, there are several ways you can do this - you could promote all the fields with info you need to the library and use a workflow (created in SharePoint designer) to copy data from your library to your calendar. You could submit your data for your calendar to the UpdateListItems method of the Lists web service using CAML.
If it is repeating, you'll either need custom code of some kind or you could use qRules - which makes submitting form data to a SharePoint list pretty simple.