Hello @Sflikkema and thanks for your question. Welcome to Square...we're so glad you're here! I think the router will be okay; it's simply a gateway to the Internet, so as long as it has wifi connectivity or the ability to hardwire an ethernet connection, I think you're router will be okay (that's more specific to your internet provider so as long as you have internet, Square should connect.)
As far as your cash drawer, those are also pretty basic in terms of technology they use. Some connect through your receipt printer to generate a signal to "open the drawer". See this post here about cash drawer compatibility. I hope this helps answer your questions.
