I currently make 90 k as a project manager and my employer would contribute up to 13 k for my studies, but given my background I don't think I could attend any top tier ones, as well as not having any nearby. GPA 4.0, mid-30s, attended an average school.

Is it worth considering an online MBA at a B school or better to focus my energies and resources elsewhere?

I don't know what your goals are. Maybe a language class or a course in a STEM field would be more valuable. Generally, postgraduate education in a vocational field is one of the best investments most people can make. 

You don't say what sector you work in or what kind of project management you do e.g. IT, construction etc. Depending on your goals maybe a project or programme management qualification via PMI might be more useful rather than a generalist management qualification like an MBA?