Rather than take you on the long(ish) trek I took to find this plugin, I'll get right to it. There is a Wordpress Plugin that lets you order blog posts within a category and it is the Q2W3 Post Order WordPress Plugin.
Surprisingly there was nothing in the wordpress.org/support forum. In fact there were a lot of people lamenting the lack of a post-category sort plugin and one person who had cobbled one together that was too rough to share.
We should also acknowledge (or "give a shout out", as the kids say) a helpful post at Perishable Press, "6 Ways to Customize WordPress Post Order" that gives six ways to do it starting with code solutions, then moving on to mostly now outdated post sort plugins but ending with a link to "AStickyPostOrderER".
We thought we had the answer in hand when we went to install AStickyPostOrderER, BUT in the process we saw just below Q2W3 Post Order WordPress Plugin.
Why did we end up with the Q2W3? Because as Q2W (we're on shorter-name basis now) pointed out that aSticky hadn't been updated in a long time - and - "Q" (as we're now calling him) said he'd rewritten their code to be lighter and with some improvements.
Did anyone actually read this far? I'm guessing you all bailed out at the first link to the plugin. Let me know, leave a comment below...