Reading and writing .ics / ICAL data is somewhat less painful when I do it through Data::ICal and Date::ICal (yes, great names ...).

Unrolling the recurrence rules seems to be available in Net::ICal::Recurrence, so maybe that is enough already for you to handle these.

Specifying a range and getting all events in that is something that I offloaded to my ICal / CalDAV server (via Net::CalDAVTalk) , which has the API already for such queries), but if you want to roll your own, likely DateTime::Event::ICal has the API you want to get dates out of recurrence lists.