DSL maybe an option there, but we don't know if that will meet her employer's "high speed internet" requirements (she grades papers for Western Governors U, get your mind out of the gutter). 95% of what she does is download an Office document and upload the graded document. Don't know why "high speed" is required, but whatever.
The kids are what I'm worried about - they use data over our wifi like crazy. YouTube, Snapchat, Instagram, Netflix, Amazon Prime... my modem says we used 695GB in January. Avg over 600GB/month from Nov through today.
Ouch. I don't know that you are going to find much for hot spot price plans anywhere near that much usage. The biggest plan for my provider is 50 GB, then $5 per gig if I go over.