I'm going to go with what may be the least amount of hassle to you, in relation to the CMS I'm most familiar with.
My example depends on what CMS/Framework you're using and if you enter the data manually, or if it's just being pulled in via some kind of API/Feed... what have you. Which it sounds like the latter is the case.
My use case is WordPress and manual data entry. It shouldn't take an experienced WP dev long to write a plugin for a single Schema type (Local Business - Event, etc.). It sounds lazy, but if you're not terribly comfortable with HTML - that alone would be a time saver.
However, if you're pulling these events in via some RSS Feed or API, that will likely require more dev time. The latter being the most dev time of all, even provided adequate documentation.
In any case, you wouldn't be able to get there without some amount of developer time/involvement. As far as I know, there isn't a plugin that handles your particular use case as I understand it.
Also, if you are using WordPress and you're using a plugin to pull in this feed - it could be about as time consuming as the second option. Plus, there's the added hassle of making a plugin work with a plugin. That wouldn't be the best idea either, but then again - sometimes my estimates are off.
Long story short, you will more than likely have to consult a developer on this one.